Thanks I will pick up some of those shims. the wing is the rc18b mount with the rc18r wing. I don't think you can put the wing mount on the stock rc18t shock towers since they are missing some holes but it will work with the RPM shock towers. I am hoping these steel diffs will hold out for a while.
wing mount:
http://www3.towerhobbies.com/cgi-bin...?&I=LXLRA8&P=Z
wing:
http://www3.towerhobbies.com/cgi-bin...?&I=LXLRC1&P=Z