Hey there gang I'm new to four wheelers and to ATV connection. I was just kinda wondering what some popular upgrades for more power are on this machine (2001 400ex). I want to get exhaust first but don't know who's is better(FMF, HMF, LRD, ETC) I like the looks of the LRD pro 4 system but like I said I have no idea if thats a good exhaust or not. I can get a FMF power bomb header and mega max silencer used for 180 bucks are those any good? Also I know you need to rejet your carb, and lose the air box lid, and get a new air filter. Any advice on that would be appreciated as well. Thanks everyone hope to hear back soon.