diff --git a/examples/04_sbends_and_radii.py b/examples/04_sbends_and_radii.py
new file mode 100644
index 0000000..cdf8826
--- /dev/null
+++ b/examples/04_sbends_and_radii.py
@@ -0,0 +1,81 @@
+from shapely.geometry import Polygon
+
+from inire.geometry.collision import CollisionEngine
+from inire.geometry.primitives import Port
+from inire.router.astar import AStarRouter
+from inire.router.config import CostConfig, RouterConfig
+from inire.router.cost import CostEvaluator
+from inire.router.danger_map import DangerMap
+from inire.router.pathfinder import PathFinder
+from inire.utils.visualization import plot_routing_results
+
+
+def main() -> None:
+    print("Running Example 04: S-Bends and Multiple Radii...")
+
+    # 1. Setup Environment
+    bounds = (0, 0, 150, 100)
+    engine = CollisionEngine(clearance=2.0)
+    danger_map = DangerMap(bounds=bounds)
+    
+    # Create obstacles that force S-bends and turns
+    # Obstacle 1: Forces a vertical jog (S-bend)
+    obs1 = Polygon([(40, 20), (60, 20), (60, 60), (40, 60)])
+    
+    # Obstacle 2: Forces a large radius turn
+    obs2 = Polygon([(80, 0), (100, 0), (100, 40), (80, 40)])
+    
+    obstacles = [obs1, obs2]
+    for obs in obstacles:
+        engine.add_static_obstacle(obs)
+    
+    danger_map.precompute(obstacles)
+    
+    # 2. Configure Router with custom parameters (Directly via constructor)
+    evaluator = CostEvaluator(
+        engine, 
+        danger_map,
+        unit_length_cost=1.0,
+        greedy_h_weight=1.2,
+    )
+    
+    router = AStarRouter(
+        evaluator,
+        node_limit=500000,
+        bend_radii=[10.0, 30.0],  # Allow standard and large bends
+        sbend_offsets=[-10.0, -5.0, 5.0, 10.0], # Allow larger S-bend offsets
+        sbend_radii=[20.0, 50.0], # Large S-bends
+        bend_penalty=10.0, # Lower penalty to encourage using the right bend
+    )
+    
+    pf = PathFinder(router, evaluator)
+    
+    # 3. Define Netlist
+    # Net 1: Needs to S-bend around obs1 (gap at y=60-100? No, obs1 is y=20-60).
+    # Start at (10, 40), End at (140, 40).
+    # Obstacle 1 blocks 40-60. Net must go above or below.
+    # Obstacle 2 blocks 80-100 x 0-40.
+    
+    # Let's force a path that requires a large bend.
+    netlist = {
+        "large_bend_net": (Port(10, 10, 0), Port(140, 80, 0)),
+        "sbend_net": (Port(10, 50, 0), Port(70, 70, 0)), 
+    }
+    net_widths = {"large_bend_net": 2.0, "sbend_net": 2.0}
+
+    # 4. Route
+    results = pf.route_all(netlist, net_widths)
+
+    # 5. Check Results
+    for nid, res in results.items():
+        status = "Success" if res.is_valid else "Failed"
+        print(f"{nid}: {status}, collisions={res.collisions}")
+
+    # 6. Visualize
+    fig, ax = plot_routing_results(results, obstacles, bounds)
+    fig.savefig("examples/sbends_radii.png")
+    print("Saved plot to examples/sbends_radii.png")
+
+
+if __name__ == "__main__":
+    main()
diff --git a/examples/sbends_radii.png b/examples/sbends_radii.png
new file mode 100644
index 0000000..fcf1e1d
Binary files /dev/null and b/examples/sbends_radii.png differ
diff --git a/inire/geometry/collision.py b/inire/geometry/collision.py
index bd20d5e..1faf6e2 100644
--- a/inire/geometry/collision.py
+++ b/inire/geometry/collision.py
@@ -16,9 +16,10 @@ if TYPE_CHECKING:
 class CollisionEngine:
     """Manages spatial queries for collision detection."""
 
-    def __init__(self, clearance: float, max_net_width: float = 2.0) -> None:
+    def __init__(self, clearance: float, max_net_width: float = 2.0, safety_zone_radius: float = 0.0021) -> None:
         self.clearance = clearance
         self.max_net_width = max_net_width
+        self.safety_zone_radius = safety_zone_radius
         self.static_obstacles = rtree.index.Index()
         # To store geometries for precise checks
         self.obstacle_geometries: dict[int, Polygon] = {}  # ID -> Polygon
@@ -131,14 +132,14 @@ class CollisionEngine:
                     
                     is_near_start = False
                     if start_port:
-                        if (abs(ix_minx - start_port.x) < 0.0021 and abs(ix_maxx - start_port.x) < 0.0021 and
-                            abs(ix_miny - start_port.y) < 0.0021 and abs(ix_maxy - start_port.y) < 0.0021):
+                        if (abs(ix_minx - start_port.x) < self.safety_zone_radius and abs(ix_maxx - start_port.x) < self.safety_zone_radius and
+                            abs(ix_miny - start_port.y) < self.safety_zone_radius and abs(ix_maxy - start_port.y) < self.safety_zone_radius):
                             is_near_start = True
                             
                     is_near_end = False
                     if end_port:
-                        if (abs(ix_minx - end_port.x) < 0.0021 and abs(ix_maxx - end_port.x) < 0.0021 and
-                            abs(ix_miny - end_port.y) < 0.0021 and abs(ix_maxy - end_port.y) < 0.0021):
+                        if (abs(ix_minx - end_port.x) < self.safety_zone_radius and abs(ix_maxx - end_port.x) < self.safety_zone_radius and
+                            abs(ix_miny - end_port.y) < self.safety_zone_radius and abs(ix_maxy - end_port.y) < self.safety_zone_radius):
                             is_near_end = True
                             
                     if is_near_start or is_near_end:
diff --git a/inire/geometry/components.py b/inire/geometry/components.py
index 10f5f8b..9dbbcff 100644
--- a/inire/geometry/components.py
+++ b/inire/geometry/components.py
@@ -34,7 +34,7 @@ class Straight:
 
         ex = start_port.x + dx
         ey = start_port.y + dy
-        
+
         if snap_to_grid:
             ex = snap_search_grid(ex)
             ey = snap_search_grid(ey)
@@ -89,10 +89,10 @@ class Bend90:
         # End port (snapped to lattice)
         ex = snap_search_grid(cx + radius * np.cos(t_end))
         ey = snap_search_grid(cy + radius * np.sin(t_end))
-        
+
         end_orientation = (start_port.orientation + turn_angle) % 360
         end_port = Port(ex, ey, float(end_orientation))
-        
+
         actual_length = radius * np.pi / 2.0
 
         # Generate arc geometry
@@ -124,12 +124,12 @@ class SBend:
         ex = snap_search_grid(start_port.x + dx * np.cos(rad_start) - dy * np.sin(rad_start))
         ey = snap_search_grid(start_port.y + dx * np.sin(rad_start) + dy * np.cos(rad_start))
         end_port = Port(ex, ey, start_port.orientation)
-        
+
         actual_length = 2 * radius * theta
 
         # Arc centers and angles (Relative to start orientation)
         direction = 1 if offset > 0 else -1
-        
+
         # Arc 1
         c1_angle = rad_start + direction * np.pi / 2
         cx1 = start_port.x + radius * np.cos(c1_angle)
diff --git a/inire/router/astar.py b/inire/router/astar.py
index 44b6b6a..b4ff307 100644
--- a/inire/router/astar.py
+++ b/inire/router/astar.py
@@ -7,6 +7,7 @@ from typing import TYPE_CHECKING
 import numpy as np
 
 from inire.geometry.components import Bend90, SBend, Straight
+from inire.router.config import RouterConfig
 
 if TYPE_CHECKING:
     from inire.geometry.components import ComponentResult
@@ -46,9 +47,46 @@ class AStarNode:
 
 
 class AStarRouter:
-    def __init__(self, cost_evaluator: CostEvaluator) -> None:
+    """Hybrid State-Lattice A* Router."""
+
+    def __init__(
+        self,
+        cost_evaluator: CostEvaluator,
+        node_limit: int = 1000000,
+        straight_lengths: list[float] | None = None,
+        bend_radii: list[float] | None = None,
+        sbend_offsets: list[float] | None = None,
+        sbend_radii: list[float] | None = None,
+        snap_to_target_dist: float = 20.0,
+        bend_penalty: float = 50.0,
+        sbend_penalty: float = 100.0,
+    ) -> None:
+        """
+        Initialize the A* Router.
+
+        Args:
+            cost_evaluator: The evaluator for path and proximity costs.
+            node_limit: Maximum number of nodes to expand before failing.
+            straight_lengths: List of lengths for straight move expansion.
+            bend_radii: List of radii for 90-degree bend moves.
+            sbend_offsets: List of lateral offsets for S-bend moves.
+            sbend_radii: List of radii for S-bend moves.
+            snap_to_target_dist: Distance threshold for lookahead snapping.
+            bend_penalty: Flat cost penalty for each 90-degree bend.
+            sbend_penalty: Flat cost penalty for each S-bend.
+        """
         self.cost_evaluator = cost_evaluator
-        self.node_limit = 1000000
+        self.config = RouterConfig(
+            node_limit=node_limit,
+            straight_lengths=straight_lengths if straight_lengths is not None else [1.0, 5.0, 25.0],
+            bend_radii=bend_radii if bend_radii is not None else [10.0],
+            sbend_offsets=sbend_offsets if sbend_offsets is not None else [-5.0, -2.0, 2.0, 5.0],
+            sbend_radii=sbend_radii if sbend_radii is not None else [10.0],
+            snap_to_target_dist=snap_to_target_dist,
+            bend_penalty=bend_penalty,
+            sbend_penalty=sbend_penalty,
+        )
+        self.node_limit = self.config.node_limit
         self.total_nodes_expanded = 0
         self._collision_cache: dict[tuple[float, float, float, str, float, str], bool] = {}
 
@@ -107,7 +145,7 @@ class AStarRouter:
     ) -> None:
         # 1. Snap-to-Target Look-ahead
         dist = np.sqrt((current.port.x - target.x) ** 2 + (current.port.y - target.y) ** 2)
-        if dist < 30.0:
+        if dist < self.config.snap_to_target_dist:
             # A. Try straight exact reach
             if abs(current.port.orientation - target.orientation) < 0.1:
                 rad = np.radians(current.port.orientation)
@@ -127,30 +165,37 @@ class AStarRouter:
                 proj = dx * np.cos(rad) + dy * np.sin(rad)
                 perp = -dx * np.sin(rad) + dy * np.cos(rad)
                 if proj > 0 and 0.5 <= abs(perp) < 20.0:
-                    try:
-                        res = SBend.generate(current.port, perp, 10.0, net_width)
-                        self._add_node(current, res, target, net_width, net_id, open_set, closed_set, "SnapSBend")
-                    except ValueError:
-                        pass
+                    for radius in self.config.sbend_radii:
+                        try:
+                            res = SBend.generate(current.port, perp, radius, net_width)
+                            self._add_node(current, res, target, net_width, net_id, open_set, closed_set, "SnapSBend")
+                        except ValueError:
+                            pass
 
         # 2. Lattice Straights
-        for length in [1.0, 5.0, 25.0]:
+        lengths = self.config.straight_lengths
+        if dist < 5.0:
+             fine_steps = [0.1, 0.5]
+             lengths = sorted(list(set(lengths + fine_steps)))
+             
+        for length in lengths:
             res = Straight.generate(current.port, length, net_width)
             self._add_node(current, res, target, net_width, net_id, open_set, closed_set, f"S{length}")
 
         # 3. Lattice Bends
-        for radius in [10.0]:
+        for radius in self.config.bend_radii:
             for direction in ["CW", "CCW"]:
                 res = Bend90.generate(current.port, radius, net_width, direction)
                 self._add_node(current, res, target, net_width, net_id, open_set, closed_set, f"B{radius}{direction}")
 
         # 4. Discrete SBends
-        for offset in [-5.0, -2.0, 2.0, 5.0]:
-            try:
-                res = SBend.generate(current.port, offset, 10.0, net_width)
-                self._add_node(current, res, target, net_width, net_id, open_set, closed_set, f"SB{offset}")
-            except ValueError:
-                pass
+        for offset in self.config.sbend_offsets:
+            for radius in self.config.sbend_radii:
+                try:
+                    res = SBend.generate(current.port, offset, radius, net_width)
+                    self._add_node(current, res, target, net_width, net_id, open_set, closed_set, f"SB{offset}R{radius}")
+                except ValueError:
+                    pass
 
     def _add_node(
         self,
@@ -194,12 +239,10 @@ class AStarRouter:
         for move_poly in result.geometry:
             dilated_move = move_poly.buffer(dilation)
             curr_p = parent
-            # Skip immediate parent
             seg_idx = 0
             while curr_p and curr_p.component_result and seg_idx < 100:
                 if seg_idx > 0:
                     for prev_poly in curr_p.component_result.geometry:
-                        # Optimization: fast bounding box check
                         if dilated_move.bounds[0] > prev_poly.bounds[2] + dilation or \
                            dilated_move.bounds[2] < prev_poly.bounds[0] - dilation or \
                            dilated_move.bounds[1] > prev_poly.bounds[3] + dilation or \
@@ -226,12 +269,10 @@ class AStarRouter:
         if move_cost > 1e12:
             return
 
-        # Substantial penalties for turns to favor straights, 
-        # but low enough to allow detours in complex environments.
         if "B" in move_type:
-            move_cost += 50.0
+            move_cost += self.config.bend_penalty
         if "SB" in move_type:
-            move_cost += 100.0
+            move_cost += self.config.sbend_penalty
 
         g_cost = parent.g_cost + move_cost
         h_cost = self.cost_evaluator.h_manhattan(result.end_port, target)
diff --git a/inire/router/config.py b/inire/router/config.py
new file mode 100644
index 0000000..f5e0529
--- /dev/null
+++ b/inire/router/config.py
@@ -0,0 +1,26 @@
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+
+
+@dataclass
+class RouterConfig:
+    """Configuration parameters for the A* Router."""
+
+    node_limit: int = 500000
+    straight_lengths: list[float] = field(default_factory=lambda: [1.0, 5.0, 25.0])
+    bend_radii: list[float] = field(default_factory=lambda: [10.0])
+    sbend_offsets: list[float] = field(default_factory=lambda: [-5.0, -2.0, 2.0, 5.0])
+    sbend_radii: list[float] = field(default_factory=lambda: [10.0])
+    snap_to_target_dist: float = 20.0
+    bend_penalty: float = 50.0
+    sbend_penalty: float = 100.0
+
+
+@dataclass
+class CostConfig:
+    """Configuration parameters for the Cost Evaluator."""
+
+    unit_length_cost: float = 1.0
+    greedy_h_weight: float = 1.1
+    congestion_penalty: float = 10000.0
diff --git a/inire/router/cost.py b/inire/router/cost.py
index 94ff177..f443879 100644
--- a/inire/router/cost.py
+++ b/inire/router/cost.py
@@ -2,6 +2,8 @@ from __future__ import annotations
 
 from typing import TYPE_CHECKING
 
+from inire.router.config import CostConfig
+
 if TYPE_CHECKING:
     from shapely.geometry import Polygon
 
@@ -11,16 +13,38 @@ if TYPE_CHECKING:
 
 
 class CostEvaluator:
-    """Calculates total cost f(n) = g(n) + h(n)."""
+    """Calculates total path and proximity costs."""
 
-    def __init__(self, collision_engine: CollisionEngine, danger_map: DangerMap) -> None:
+    def __init__(
+        self,
+        collision_engine: CollisionEngine,
+        danger_map: DangerMap,
+        unit_length_cost: float = 1.0,
+        greedy_h_weight: float = 1.1,
+        congestion_penalty: float = 10000.0,
+    ) -> None:
+        """
+        Initialize the Cost Evaluator.
+
+        Args:
+            collision_engine: The engine for intersection checks.
+            danger_map: Pre-computed grid for heuristic proximity costs.
+            unit_length_cost: Cost multiplier per micrometer of path length.
+            greedy_h_weight: Heuristic weighting (A* greedy factor).
+            congestion_penalty: Multiplier for path overlaps in negotiated congestion.
+        """
         self.collision_engine = collision_engine
         self.danger_map = danger_map
-        # Cost weights
-        self.unit_length_cost = 1.0
-        self.bend_cost_multiplier = 100.0 # Per turn penalty
-        self.greedy_h_weight = 1.1
-        self.congestion_penalty = 10000.0  # Massive multiplier for overlaps
+        self.config = CostConfig(
+            unit_length_cost=unit_length_cost,
+            greedy_h_weight=greedy_h_weight,
+            congestion_penalty=congestion_penalty,
+        )
+        
+        # Use config values
+        self.unit_length_cost = self.config.unit_length_cost
+        self.greedy_h_weight = self.config.greedy_h_weight
+        self.congestion_penalty = self.config.congestion_penalty
 
     def g_proximity(self, x: float, y: float) -> float:
         """Get proximity cost from the Danger Map."""