Peepstang9

I just bought a brand new 2003 GT. It is an automatic (dont start, ive heard it all before). It is pretty quick, but could be quicker. It is definetly not loud enough. Does anybody have any recommended mods that i could make that would a few horses, and make it louder, but at the same time will not void the factory warranty. Thank you.

stanglover

Get longtube headers, 2.5" Magnaflow cat-back and take the cats out if they aren't strict with emmisions.

LINEITUP

I like the way mac sounds and its got the best numbers of horsepower gain than all the rest

stanglover

Really? Do you know how much hp?

kaboom

yo line it up what does your car do in the 1/4 with and without the squeeze

brockleew

I suggest gears first. Those 3.08s or 2.73s you got in yer car suck big time. A nice set of 3.73s, 3.90s or 4.10s would really wake that motor up and throw a suprizing smile on yer face. Theres a few hp sitting on that stock pully system of yers, underdrive pullies ad 7-10 hp off the bat that is very noticable. If you dont have a CAI, get one. Everyone has their own preference to which brand to buy, I bought Steeda ofcourse but the best dynos I have seen were Disenchargers. Somewhere between 4-10 hp depending on exhaust. Next get a nice catted x-pipe to stay emission safe. Bassani puts out the best results from what Ive read and alot of people say many great things about them. If you have the cash install that x-pipe with a cat-back at the same time. Peeps that say get headers first have the right idea but are going in the wrong direction. If you get a free flowing header but it leads into an h-pipe that has 6 cats on it, yer getting zero improvement on hp. The onlything that might happen is that you create equal back pressure on the exhaust stroke of yer valvesgiving maybe a hp due to efficiency of the engine work. Im not sure how much yer willing to spend, but if you do things in order this should work out to be the best bang for the buck. GL on yer upgrades. Hope my 2 cents helps. </P>

Jugador

6 cats? do stockers have 6?

Redline5th

Your looking at 1000 dollars for just the Exhaust system alone...(Xpipe 300$, headers 400$, pipes 300$) I would go with either Mac or Flowmaster on the exhuast...Don't forget a air intake!

Zcpeanut

Dont worry about the HP for now, get yourcar sounding the way you want and then im sure you'll be pleased with the amount of hp gain from the MAC headers, bassani X pipe, and stage II flowmaster or if u got the $$$ borla exhaust (sound freakin sick)... but the catback borla is 725$ not to mention the MAC or bassani x pipe, just so you know its a common ? whats the diff btw the offroad x pipe and the normal... the offroad dont got cats

jeep45238

You're looking at under $700 for an easy 100 horsepower gain called "nitrous oxide", and contrary to popular myths, it is perfectly safe when one knows the dangers and the proper way to use it.