I too ended up doing my shocks via the top, I've got too used to Tamiya TC shocks.
As far as the undertray goes after 1 meeting with it held in place with the supplied double sided tape I decided to get a body reamer and put holes in it to allow two of the rear gearbox screws to hold it at the back and used one of the servo mount screws on the side. Slightly more fiddly than double sided tape but won't go off like the tape and need replacing.
Has anyone re-drilled their chassis to move the battery post over and allow easier access to the motor, I was thinking of trying this but I didn't know if it would cause problems holding the cells in?
Jimmy, the rubber hinge pin mountings are actually an HPI part off their nitro car so if you need spares or replacements the part number listed in the manual is an HPI part number not a Hot Bodies. Just for future reference as the man in my LHS couldn't find a price for them under HB but found it by part number under HPI.
telboy, to someone with little imagination and even less practical talent your shell looks great and worthy of the effort that it undoubtedly took.