With the freeing up of the exhaust flow that comes with headers, don't you lose a lot of bottom - end torque. I've already lost some with my larger exhaust system. Would the increase in HP be worth the loss in bottom-end grunt?

since you have a n/a car i would recommend the *&* headers, they have 1.5" primaries as compared to the togs or the slp'* that have 1.625" primaries. ive heard nothing but good things about puttin headers on the series 2 motor

I think the only way to find out for sure would be track runs or dyno to see where the power shifted to.

It'* not a bad mod at all. But you should really to mods to compliment it so your not dissapointed. Stuff like a cam, or rockers and a hvii all move your powerband up to where headers will help you out.
If your on a mission to get close to 13s or possibly into the high 13s then i'd say do it. but if not, save some money, and get GOOD pems with a cut and welded rear mani.

BTW, what shift kit do you have? You've got a 4T60-E right? What gears do you have?

4T60-E, yes. I dont know who the manufacurer of the stage one shift kit is, but the gearing is stock.

you wont lose torque, the powerband is just changed. Headers are a great addition to any motor, they make it much more efficient.

You will loose low end torque to gain more high end power. But without a cam or rockers you won't be seeing any of this high end power any time soon.

Ohh, by the gearing question i wasn't sure what your car came stock with. Is it a 3.06 final drive?

Headers give you a power jump everywhere, if made right. They must "help out" or "scavenge" well with other cylinders, having lengths timed just right, to pull exhaust out as good as possible.

I really don't know to be honest. Anyone?