I had topspeed headers, when they first came out there was a dyno of them on a stock Z and if i recall it made around 12whp, dont expect that if you already have exhaust work done but you should expect a noticable gain in power. I definately felt them in my butt dyno.

 

nice then i know im goin for those to save money so i can get the topspeed catback with it next month. Were they easy to install or would u say take it to someone at a shop?

 

I did them myself, its not particularly hard, just very very time consuming, having a buddy to help you will make things easier, it was a weekend project and we took our time.