Hello, after much debate I finally purchased a 04Auto. Paid 31 for it which seemed fair. Anyways I am wondering what are the best mods I can do to it for performance. Thinking exhaust for sound but can I gain any RWHP with any of the exhaust systems available. Otherwise what are some of the best mods I can do. Also what kind of costs and gains can I expect? Thanks.

Jason

 

An air intake system will get you anywhere from 10-16 Rear Wheel Horsepower for $250-$500. Here's what one guy decided:

https://www.corvetteforums.com/m_11634/tm.htm

A cat-back exhaust will get you a couple of RWHP at best (in a relatively-stock C5) and you are correct in that they are purchased primarily for sound. For additional bucks, you can have 3.42 gears installed to really wake up the "feel" of acceleration. That and long-tube headers will add speed, but for more than $1000 each.

dave

 

Welcome Jason, and congratulations on your purchase
Depending what you want to do, and how much you want to spend you could spend a small fortune on this. Anything from C.A.I, to cat back exhaust, headers or even supercharge it (Mucho bucks $$$$).
The first thing I did was put the Borla stingers on it, and as you and Dave said not a whole lot of HP here, but you have to love the sound. My next mod was the Cold Air intake from Callaway. The Callaway honker is a bit pricey (around $500.00) but it's a nice, well designed setup. Heres a previous post of my thoughts on the install https://www.corvetteforums.com/m_15287/tm.htm
You could go with an aftermarket MAF sensor such as this one from Granatelli http://www.corvettegarage.com/produc...-corvette.html. Or how bout just a larger throttle body such as this http://www.ecklers.com/product.asp?p...dept%5Fid=1304.
Your biggest HP achiever will be headers, and you will definately notice the HP gain here. This will probably be my next mod after the first of the year. This performance shop here in town will install a set for $1200.00.
So it's really what you decide and how much your willing to spend. Your not going to get huge performance gains just a little at a time. Good luck!

 

Thanks for the advice. Sounds like a cat back and CIA will be my first mods once I swallow the purchase price LOL. How are the stock computers. Are they pretty much well tuned for power or does Chevy give them a tame tune from the factory? Also does anyone know stock average RWHP? Finally can anyone give me advice on if I should purchase an etended warrenty? If so anyone know of any good places to do so? Thanks again.

 

Check this post from some months ago, far down in it I list some test results for various vets. You generally loose about 8-12 Hp more to the RW through an A4 than the M6

https://www.corvetteforums.com/m_10712/tm.htm

 

You will gain up to 10 RWHP by having your C5 dyno-tuned, but this service isn't cheap ($400-$600). My stock RWHP and results of modifying are listed below:

315.9 RWHP 337.7 RWTQ (Dynojet) 6/8/02 (no mods)
328.8 RWHP 352.2 RWTQ (Dynojet) 5/22/04 (mods listed below)
Quad Round Borla Stingers 9/6/03
Halltech Stinger-R intake system 4/17/04
Cold-air scoop mod 5/20/04
BPP shifter with dampening mod: 12/26/04
Shift ****, intake install and CAI mod: www.conceptualpolymer.com

Warranty Direct and GM's GMPP offer good extended warranties.