It really depends on what you plan to do with it!
You can go diff or 2-speed in the center.
Hook it up with traction drive from Tekno RC.
Change out the stock bearings for ceramic bearings from Acer Bearings.
Get cf parts from SNR Graphite(chassis, shock towers, radio tray)
Hook up the body and wheels from IGTHobbies.
Better yet sell it for a DM-1 Spec and get the Tekno conversion......
Just kidding it's just what i run.