I'm evaluating this based on a cost comparison. SC kits are more expensive (when compared to Mech Tech). Why would you pay more money for less power? Plus, there is not one SC kit out there (besides G-power) that actually performs well. Although you SC owners might think your SC is making power, it in fact is extremely inefficient was never meant to be on a BMW engine anyways. Vortech blowers are engineered for V8s (with the exception of a few 4 bangers). Have you been to Vortechs site lately? Seen anything about BMWs? Nope.