a good start is to get some nerf bars and then make the bike wider by putting a new +4 rear axle on and +2 a-arms. You then can buy new shocks such as Elka and also buy some new pipes, DMC, Toomey, Paul Turner, FMF, Pro Circuit. There are alot of different pipes to choose from.
You can get good deals on parts from RockyMountainATV.com
hope this helps.