Any good brand name exhaust would be great LRD, FMF, CurtisSparks, you will have to rejet the carb move the clip on the needle, you can change the cam i would put a HotCam stage 2 take the breather box top off for more air since you are going to rejet anyway, you can even change the piston out with a higher compression but don't go over 13 to1 or you will have to run race fuel 9 to 25 $ a gal depending on what octane you get.