im pretty sure the stock srt-4 will not put out 500 horses. maybe if you slam on headers, exhaust, turbo(or supercharger) some nos, new tranny and drive components, gearing, and everything you possibly can itll put out 500hp easily ya. but not stock. I just looked it up so dont argue with me.
2.4-liter turbocharged 16-valve double overhead camshaft (DOHC) engine
230 horsepower
250 lb-ft of torque
Zero to 60 in around 5.8 seconds
Quaife automatic torque biasing (ATB) differential
right from the source of the car itself
http://www.dodge.com/srt-4/
I was passed by an Srt-4 once, and needless to say I wasnt going slow. The guy passed me like I was standing still. So yes it is a fast little car. Is it a 500hp V8 rwd monster...no. But itll still go fast enough for any persons needs.