E46 M3 Valve Guides

GSC Power-Division valve guides are made from a proprietary blend of Manganese Bronze and turned on dedicated precision CNC turning centers. With performance and aftermarket installation in mind, we hold extremely tight tolerances on through-hole concentricity to outside diameter which minimizes the required honing time for the installer. True-to-size outside diameters minimize honing of guide bosses on cylinder heads that don't require boss service. Our guides are easier to install and shaped to improve air flow instead of just copying OEM design.