We (#1447) mated both the FP and Bosch motors to DeWalt three speed trannys, which are superior to the Bosch trannys - the shift ring gears are all metal and will shift on the fly, especially if you radius the inlets.
We cut our own 32-15 pinions out of 0.3" titanium on our (USA-TARDEC) watercutters and pressed them onto the motor shafts. Used Loctite 680 retaining compound just to be sure the press fit would hold. Drive setup worked great except that our mounts didn't hold the trannys well enough; they wanted to spin, so we retrofitted a bolt through the nylon assembly. Too bad that our proto-type was only used for photo-opps, we'd have discovered the problem well in advance instead of staggering through so many matches
