Did you rejet and do airbox mods at all? I understand that makes a lot of difference with the pipe. If you have done this and it still doesn't make much difference, I'd definitely like to know.

I also have the same type of question. I'm trying to decide whether to order a GYTR slip on or go for a full exhaust like Trinity, DMC or CT.

 

Unless you have internal motor work done, you will be throwing money out the window if you buy an aftermarket header pipe for a 4 stroke.

 

Both the Raptor and the Warrior have quite large headers and, as the previous post has said flow adequate exhaust from a stock engine. Not so with some Honda quads & bikes. An after market header on a Raptor or Warrior would serve cosmetic improvement only.

 

I started with the big gun silencer and it made a difference right away, added the header later but noticed no or very little difference. Before adding a head pipe you might want to add an aftermarket airfilter, open up your airbox and put in a dynojet (or k&n which is the same thing) kit. you should notice a great improvement