i only have enough to get either the gm cat-back exhaust or the gm header. I already have an AEM cold air intake. Right now all i care about is power, what should i get. I was thinking maybe the header and a bolt on muffler if someone has one out or a gm muffler but im not sure if they have one. Please give me your advise.

 

order you a header and get a Magnaflow off ebay. they are like half price on there

 

Save your money to purchase them both so you can install it in one shot. It will save on installation charges (if you're taking it to a shop). Even if you aren't taking it to a shop, it'll make installation easier.

Also, I suggest getting a Magnaflow Cat to keep the exhaust diameter the same between the 2.

 

would the manga flow void my warrenty?

 

it's going to void your exhaust warranty, or that is what I was told anyways

 

No.

The item has to directly effect your engine problem.