Quad 4 Performance

So I'm looking for some performance parts for my new achievas and the only one I can come across is Mantapart. Anyone know any more sites?
(I'll update if I find more)

I wish I could tell you the sites. But I dont know. One thing I do know is you may want to look around at some open wheel dirt racing sites. There is a whole class around the quad 4. I know a guy whos dad has one. With that there should be alot out there. Finding it is another thing.
Good luck & hope it helps in your search.