i put a 12 tooth sproket in the front and a 46 tooth sproket in the rear.. i love it now..it has alot more lowend..instead of launching you with all the tork its more like slow pulling tork.i also bought aftermarket plus 2 inch steel arms and im gonna get a lowing kit and 3 inch wheel spacers for the rear..

 

i honestly wouldnt mess with the axel or a-arms if your gunna be trail riding this thing. the wider you are the more youll be hittin things. depending on where you live theres a lot of trails where you sometimes just barely make it by.

an now if you do choose to widen it in the rear id try to stay away from wheel spacers. they are cheap, but they put a lot of stress on the hubs an wheel studs. the route to go for stronger an still less expensive than a whole axel would be extended hubs. i believe g-force makes a set.