Unless you go massive port job and massive cam twin webbers wont to sh-it. You onle need the webbers if your building a race engine for extreme rpm. The twin 1.5" hitachi su's will do fine to 8000rpm and probably more. The fuel/air system alone does not boost power. You only need to upgrade air/fuel system to accomodate other things like cam, porting and compression. Take this advice and save yourself alot of money that could be spent elseware on making the car faster. Brakes, suspension etc.