Well, the first thing I would do is a little tricky, you will need a dremel or something similar because you will have to cut both the front & rear housing where the diffs are because rocks can get trapped there and the belts will snap. Also if you want it to drift you can lock the the rear diff, I used a glue gun & then change the front diff to a one way unit. With that setup it will perform pretty good. Right now I replaced some parts to aluminum & I also replaced the chassis to aluminum so it would add some heft to it. Oh yeah you probably want to replace the dampers to aluminum. As far as the bodies, there's a lot of body options, I just bought the HPI Lexus ISF body for mine.
http://www.hpiracing.com/products/en/17542/