Im pretty new to this force induction thing, but I have done my homework and I do understand it. However im still kinda confused on centrifugal superchargers, you know the turbocharger that is belt driven? Do these types of superchargers produce more power than a turbocharger? I have a 1999 Si and Vortech makes a system that claims to add 117 horsepower at 9 psi. Than theres procharger, who doesnt give an exact horsepower gain, rather a percentage. 70%-75% gain. If I were to get a turbo i would go with the turbonetics system, they take my 160 stock hp to 250. If anyone has a syno chart or something for these systems that would be great. Which system is best?