I just bought a brand new 2007 AC 650 H1. Ive been preparing to start a local cross country utility class for awhile. I know a pretty good deal about four wheelers but not quite as much as I see some of the people on here know. Anyways, I know that some utility racers race in 4wd and some in 2wd. I know the advantages of this and I prefer racing in 4wd in on the trails due to the ease that the quad climbs over and tackles tough terrain and on the banked and rutted out corners (it is slightly harder to turn) the 4wd hugs the corners and pulls you out faster. It also prevents the rear end from breaking loose on soft terrain. I was wanting to know if there were any differential, u joint, or any other axle pieces you guys would recommend for such high impact on 4wd. Thanks