Go Fast Bits GFB 13 Subaru BRZ / 13 Scion FR-S 3 Pc L/W Pulley Kit (Inc Crank/Alternator/Water Pump Pulleys) - 2016 $350.00 $315.00 It might be hard to imagine how reducing the mass of a pulley makes a car go faster, but accelerating a heavy factory pulley from say 3000-7000 RPM in a second or two saps a measurable amount of torque. GFB Lightweight Pulleys reduce inertia by up to 85... Add to Cart