PFF5-5601G offers an additional +0.5 of caster over PFF5-5601 and is a high performance option to PFF5-4601, aimed at offering greater precision with improved geometry for people wanting the very best from their E46 or Z4. This new part, fitted to the rear of the front wishbone has a hard anodized aluminium outer shell with one of our unique low friction polyurethane center bushings. The poly/aluminum combination creates a low friction rotating bushing 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. This bushing is designed to fit the 66mm aluminum bushing housing. Please ensure you have the correct size bushing before fitting. Testing during the development of this bushing has indicated stiffness gains of 128% compared with the original rubber bushing. Our Black Series part increases stiffness by 28%, to give an 190% increase in stiffness over the original part.