I have a 2004 Pontiac GTO what performance should I begain with to raise the horsepower in my car?
It depends on how long you want the engine to last and whether or not you are willing to void any lingering warranties (like a 10 year/100,000 mile drivetrain warranty).
If you don’t need to make this engine last, and you don’t care about voiding the warranty, I would start with a custom air intake by K&N and a custom exhaust by Flowmaster. If that doesn’t give you enough horsepower, I would look for an aftermarket cam shaft with lobes designed for maximum power. Of course this upgrade might lead to failure of emissions testing, and will definitely shorten the time between engine rebuilds.
What about time between power pulses 
OP what engine are you starting with? I don’t think you will be at all satisfied with the return on money spent for the air intake and the exaust work (minimal return,may sound cool).
For Stage 1 how much HP gain do you want?
LS1 Engine and I want my engine to last and the most i can spend is 3,000… for now… What about a super charger… what goes with that
Double your horsepower with a nitrous oxide kit.
I would say to get a Summit Racing catalogue. Your engine is not low performance as it sits,what I mean is the easy stuff has been done. Super,Turbo,Nitros all will get you there it is just maintaing both your budget and the desired reliability.
If you want the engine to last, I would put that money towards maintenance. Maintaining this car will allow it to perform at its best without shortening its life.
The LS1 is the same engine they use in the Corvette. I think it already comes with enough performance. Keeping up with oil and other fluid changes will allow it to continue to perform at peak performance.
If you want the engine to last and the maximum you can spend is $3,000, you’re extremely limited.
I’d recommend against a K&N system because the gain will be negligable and they oiled filters have been known to contaminate mass airflow sensors.
Superchargers, turbochargers, a custom cam, and all of these things (especially N2O) place added stresses on the engine parts and reduce the reliability and/or lifespan of the engine. Custom cams require other parts to run properly, like roller bearing lifters and different rockers and return springs. Otherwise the valves may “float”, not close at higher RPMs.
Probably the best you can do that won’t affect reliability is a better exhaust system. The gains will be extremely minimal, but the reliability won;t be affected. Your budget is way too limited to get fancy.
You want it fast.
You want it cheap.
You want it to last.
Pick any two.
BTW, the term is “soup up”.
If you increase your HP, you first need to upgrade your suspension, brakes, clutch, exhaust, fuel pump, injectors, etc. It may be easier/cheaper to sell your car and buy a faster one.
Twotone
I suspect that GM already has a low-restriction exhaust system on the GTO. I suppose that you are including headers in this suggestion for a new exhaust. That might work, even if they are legal.
You may be right JT. And yup, in that case I’d suggest headers.
Much of what you can do on a limited budget without affecting reliability is largely a placebo-effect gain anyway. Perhaps a body kit would be a better idea.
I would start with a custom air intake by K&N and a custom exhaust by Flowmaster
Personally I would not go that way. First most modern cars breath very nicely stock, so there is very little to gain working with intake and exhaust unless you do a lot more to the engine.
Also K&N filters come in two types. The oiled filters can cause MAF problems if they are not carefully oiled and many people do not carefully oil them.Don’t forget the transmission as well.
Everyone was a big help in my decisions thanks again
With virtually all OEM parts there are concessions made to keep the bean counters happy. And while stock exhausts are better these days, there are still some gains to be had in most cases. SLP and Lingenfelter have some nice parts for the G8 and GTO