Mods to get:
-Aluminum rear pivot block(Trinity, RCTrix, etc..)
-Captured ball ends or titanium ball studs for fr/rr camber links.(I use Mugen MTX-2 captured ball ends).
-A "Dace" brace, aluminum battery box or a battery box skid plate/protecter to reduce/eliminate battery box breakage.
As for engines I use an OS .12 CVR or a OS 12TR. The truck comes equipped for side exhaust engines though so you will need a rear exhaust manifold if you want to run a R/E engine.
Check this thread for pro's and con's:
Choosing 2wd 1/10 gas trucks for racing