PFF5-5601GM3 offers additional +0.5 of caster over PFF5-5601M3 and is a high performance option to PFF5-4601M3, and aimed at offering greater precision for people wanting the very best from their E46 M3. This new part, fitted to the rear of the front wishbone has a hard anodised aluminium outer shell with one of our unique low friction polyurethane centre bushes. The poly/alu combination creates a low friction rotating bush reducing the forces acting on the arm. Lower arm deflection has been decreased by reducing the compliant material within the aluminium shell. Results are less movement in the arm under cornering and braking, improving steering control and feel. For the M3 models which have a thicker wishbone. Please ensure you have the correct size bush before fitting. Testing during the development of this bush has indicated stiffness gains of 128% compared with the original rubber bush. Our Black Series part increases siffness by 28%, to give an 190% increase in stiffness over the original part