how much would an upper Plenum and a 75mm throttle give me in hp on my 2003 mustang GT?.....im looking at buying one but want to know if its good for the $$

 

Maybe 5 hp.

 

there are 3 things good for power on these cars worth the money.

1) gears (no horsepower added but will make your car noticably quicker)
2) long tube headers (expensive and a pain in the *** to install)
3) forced induction (supercharger, nitrous, turbo)


if you want a couple good, cheap mods remove the air silencer and get a K+N at oreillys, and get an offroad midpipe then change out your mufflers or get a catback. and a short throw if u got a 5sp.