how much HP with headers on 2005

How much will I gain, is it worth the $$ or just stick with muffler and cold air induction?

a header might give you a few extra horsepower. but it would work alot better if your engine needed it. i mean, if you make the car use more gas and suck more air, you're deffinitly going to need to upgrade your exhaust. but if you're just running stock cams, injectors...ect. you don't need to get a header. it wouldn't make enough of a difference to even notice. spend your money on something more useful. like a programmer for your ecu.

a header might give you a few extra horsepower. but it would work alot better if your engine needed it. i mean, if you make the car use more gas and suck more air, you're deffinitly going to need to upgrade your exhaust. but if you're just running stock cams, injectors...ect. you don't need to get a header. it wouldn't make enough of a difference to even notice. spend your money on something more useful. like a programmer for your ecu.

there is no programer for the ECU, the 2.4L and 2200 engines will have a programmer in the next month or so. The ecotec will follow that a little later