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The GFB lightweight underdrive pulley kit for select Subaru WRX/STi and compatible models reduces rotating mass to sharpen throttle response and improve acceleration. CNC-machined from 6061-T6 billet, the two-piece kit replaces crank and alternator pulleys and works without supporting mods or tuning. By cutting inertia up to 85% and underdriving accessories where applicable, it frees torque for the wheels while preserving accessory function.
GFB 02-10 WRX/STI 2 Piece Under-Drive Pulley Kit w/ Belts (Crank & Alternator)
