These aren't plastic models, they are RC's which ARE meant to be driven Personally I am not a huge fan of Tamiya Rc's due to them breaking easily, but yes parts can be bought to fix up if that happens.
Looks like RTRs & BODIES are starting to be circulated Still a bit too pricey for the body IMO Ready to Run: http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXCBBP&P=7 Body only: http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXCBCX&P=7#tech