The only time I stipped the gears off one of the hardened clutchbells is when I used a Kingheadz EZ Change engine mount(not the extended one).
What happened was the kingheadz mount uses a 4mm screw and a 4mm nut to hold the engine mount in place, but the only thing really holding the engine mount is the compression between the screw and the nut.
So at a recent demo event I launched my TR repeatedly over some huge 8ft ramp that launched my truck 20 ft in the air. And it was after a few landings the gear mesh worked loose and killed my clutch bell.
Love the kingheadz mount cuz its so beefy, but I went back to the stock engine mounts for now.
As for clutch, I am using the 1.0 springs with the blue shoes. Gold springs don't suit my driving. A majority of the people prefer the gold springs and blue shoes with the trucks though.