The battery/esc tray is available as an option in the battery tray listing
http://www.rc-monster.com/proddetail...MFPbatterytray , and the Servo/Rx box is available separately as an option in the radio box listing.
http://www.rc-monster.com/proddetail.php?prod=rcmrxbx
Regarding the body - while gearing will ultimately play a role, I would expect to use a body other than stock to avoid interference, as most nitro buggy bodies are quite low slung these days. The Losi E-buggy body, for example, is used on many 1/8 E-buggies.