Okay, I did some looking on the web, and the only 2 companies I have found (in about 5 minutes of searching) with pipes for the mojave are FMF and Supertrapp. Supertrapp makes the 4" race series muffler and the IDS2 muffler, and FMF makes the Megamax pipe. You should be able to get the megamax pipe for less than $200 if you shop around. It's a good pipe. I've known lots of guys that have used them on Warriors, 400ex, 300ex, and Wolverines. Try www.atvaddiction.com
I have gotten alot of good deals from them. Good luck!!