Fine tuning an engine requires modification of every little aspect of the engine, so don't over look the Tomioka Racing Lightweight Alternator Pulley for Subaru BRZ ,Scion FRS and Toyota FT-86! This high quality aluminum pulley help alleviate engine load by reducing the rotational mass of the engine by reducing the alternator pulley weight by over 60%. Factory alternator pulley weight is 0.40LBS (181g) and TR alternator weight is 0.15LBS (794g). Every little bit helps when you are building a faster engine!