Motor Mount & Single Speed Hub Conversion:
http://www.tdracingrc.com/TD%20Product%20Line.htm
Battery Tray: (50x150)
http://rc-monster.com/proddetail.php...MFPbatterytray
You can have your pick of receiver mounting options and ESC mounting options by fabbing up some plexiglass.
Very easy conversion and well worth it IMO.