Originally Posted by ussoldierforhire
I think the difference is negligible. Macht Schnell claims gains of 9-14hp and AA claims 12+ hp. Both claim factory harmonics stay in tact. Only differential I see would be price and AA has a $50 off sale right now.
Also MC has 2 pulleys to install where AA has only 1. I have the AA and installed it myself in 45 minutes. I love this thing. Made the car a completely different animal