I wanted all aspects of performance,but not in huge quantities..When you start sqeezing every last bit of power out of any car, it requires constant tweeking and work to keep it running right..That's why I chose the sport 500 turbos and the rest of my performance mods..I wanted my Z be fast,without being dangerous and difficult to handle on public roads..I believe anything over about 550 horsepower is hardly usable on the street..Then you run into annoying lag problems with huge hp Z's etc.etc..So in short to me power=speed..I love them both..That's also why I love sportbikes..The sensation of speed is nothing like a car(total rush)..