Tom sold you out huh, Martin you need to talk to that boy......
The pinched motor is the 25T GT tuned motor from Tamiya. It is not a rebuildable unless you were used to running the old Midnight Stock motors where they just needed a little "persuasion" for a good cut.
LW suspension is in for hop-ups so Uni's should be just fine as I read the rules. Along with anything bolted to it........
As for the diff it should work it will just need some creative shimming. It overall is narrower but still offset for the pulley. I know the spool will not fit from the 415.