what should i buy first throttle body spacer or exhaust headers? what will add more horsepower? also what is a better design in exhaust headers jva or headman street headers

The headers but without a high flow cat and cat back exhaust system I doubt they will help all that much. I am skeptical of the throttle body spacers, without a proven dyno chart I would say they are a waste of money.

An air intake system coupled with a performance exhaust system could give you a noticeable HP increase.

I contacted Airaid and they cannot back up their throttle body spacer performace claims so these are just hype.

I have seen where they tested the throttle body spacers, and there is no more performance produced from them. They look nice tho...