Besides the spline count and bigger clutch is the gearing different between a justa and "S" transmissions?

 

Opps gen2!!

 

Yeah, I don't tink the Justa can turn the overdrive gear that's in the "S" tranny. All 6 gears are different as well. Probably has a lot to do with the power band of the car.

 

Safe to say that they are engineered to deal with vastly different amounts of tourque...
I know gen 1 and 2 are very different, but as an idea of whatvmaybe be different, look at the gen1 justacooper howto, for from a midlands 5 to a getrag 6...
Then use one of the 2 on line parts schematics and compare parts #'s...
Real oem, or penskie parts....

 

Gen2 mini's are more finely engeneered than gen1 mini's, so I doubt a swap of that nature would work as well. Gen1's are pretty flexible, but to get more efficiency and a better ride, gen2 seems to be much less less flexible as far as parts interchangeability goes IMO.
Good Luck!