Looking for suggestions and comments about easy bolt-on LS1 power mods that won't void the warranty (or at least easy to put back to stock if needed). You know, things that won't hurt driveability, but will bring power up close to 05 standards. Oh yeah, all this and staying within a modest $2000 budget.

Of course, I learned long ago not to trust advertising claims of HP gains. I prefer seeing independent dyno results if possible. I want quiet (no more cops or tickets please), so headers or SLP Loudmouth exhaust system is out. Here are my thoughts... CAI, free flowing full length exhaust, programable tuner, hipo MAF sensor, maybe lower temp thermostat?

LPE Cold Air Induction looks good. I've heard great things about the Corsa, Spintech, and Stainless Works exhaust systems. I'd like to get an entire system from the maniford back, including free flowing cats/mufflers, mandrel bends, and bigger diameter S/S or aluminized tubes. Been eyeing the Superchips TriTune Max Microtuner. Maybe the SLP 85mm MAF sensor, and perhaps a 160 degree thermostat.

Hoping that more intake and exhaust flow, plus running cooler, and tuning everything together should make some difference. Maybe at least 40 HP and a nice toque increase. Looks like these things should come under my $2000 budget too, I hope.

I had an MTI intake, JBA shorty headers and a Borla exhaust on my 99z28 and they still fixed my car under warrenty. (my local dealership).
I just said nothing about my mods to them when I dropped it off. Came back when they said it was ready. I was waiting for the service manager to say something about my mods but he never did. Sometimes the mechanics just fix the car and don't report the mods on the car.
Every dealership is different.

I got warrently work done on my WRX and it had 4k in mods.


About using Superchips, becareful. I will never use them again. I got a custom programmer from them for my LS1 z28. It totally screwed my car up. I also got terrible customer service that went on for months. I could never get my car to run correctly after using it. I also know several others that have had a similar experience with them.
I shipped my programmer back to them for a replacement program (to hopefully make my car run right again) and it took them 1 1/2 months to return it to me. The new programer screwed my car up worse than the first one.

On my other Z28 I used Hypertech. The Hypertech programmer worked great without any issues.

I've eliminated the Superchips tuner from my list. I was reseaching the web and it looks like the Predator is better and offers more tunes. Haven't heard much about Hypertech. I need to check it out.

I'm also hearing mixed things about changing the MAF sensor. Starting to think it's not much help unless the car is really modded a lot. Even heard it can cause problems in some situations.

Thinking this will be a two stage performance upgrade. For now since it's brand new... like CAI, cat back exhaust, and hand held tuner for now to tide me over. That looks like about 25 to 30 HP with a nice torque bump too. Later, when I'm not so worried about warranty, maybe slap on headers and slip in a hotter cam.

After lots of research and poring over dyno results from others... here is what I'm ready to order.

SLP mid-length headers with high flow cats and SLP Proflow cat backs. This will be a complete exhaust system all the way back. All exhaust parts are on sale for 10% off at TByrne's already low prices until 2/13/05. The mid-length headers have the advantage of being easier than the long tube to install. You don't have to drop the steering rack. Dyno results show close to a 20 HP gain to the rear wheels when combined with cat backs.

Still deciding which CAI to get. To stay within my $2000 budget I have narrowed the choices down to Speed Inc. or New Era. Either of these seem to get 10-15 HP on the dyno. A freebie thing I'm doing is to do the throttle body coolant bypass mod which means cooler air enters the intake which is good for a little more power.

Top this off with a Diablosport Predator handheld programmer for a nice custom tune. People seem to be getting 10-15 more ponies with the Predator. I know a professional dyno tune is better, but when you live in the middle of nowhere like me, you ain't going to find a dyno tuner, let alone a good one.

So, with a small investment of about $2k, I should be able to run with the 2005 GTO big boys and still grin about saving $8k.

If your trying to stay on a buidget then dont bother wqith exhaust mods on the GTO, most if not all cat back systems give under 10 engine horespower, meaning almost no RWHP. Borla gives 12 I think at the engine. If you want to get the most power for the buck get long tube headers, they will be a bit louder but they make much more power than the mid length and are well worth the inatall.

I would also suggest some drivetrain parts, like a lightweight flywheel, and new plugs and wires also.

You are right about the cat backs only being good for 5 HP or so, but combined with headers I still think it's a good investment. You are also right about long tube headers adding 5-10 more HP than the mid-length headers. Also note that short headers (like JBA) have very little gain over the stock manifolds.

But, the mid-length SLP does make up to 15 HP over stock and has the big advantage of being easier to install for us shade tree weekend mechanics that don't want to pay big shop labor fees. All long tube headers require you to drop one side of the steering rack on the GTO. If done correctly, you probably should have it aligned afterwards too which adds to the price. I'd rather sacrifice a few ponies to be able to do it myself and save a few bucks.

The 15-20 extra HP with the SLP mid-length headers, free flowing cats, and SLP Proflow cat backs are indeed worth it to me, especially if I decide to add a bigger cam later when the warranty runs out. The other reason to change exhaust is for the meaner sound. Let's face it, a deep throaty growl will turn heads.

You should deffinatly get a nice HP increase with the header back system, cai, and predator tune. Get some sound files for us after the install! :D