I think I miscommunicated. It's my understanding that the Kinner-engined version has now moved back to the theoretical from the actual. So what I was getting at was if you were doing it again (and setting aside the caveat that if you were doing it again from scratch, you wouldn't use two 90-degree boxes), do you think that one of the PTO boxes would be a better alternative than the 3000 diff?
Ahh, you're asking about a lessons learned kinda thing.
I'd skip all that noise and orient the engine and transmission to fit a short driveshaft to a boat v-drive. you can get a 1.65:1 overdrive ratio in there. that would turn the motor's 1950rpm to 3200rpm and i'd put that strait into an audi diesel transaxle so it has taller final drive.
I'd link the engine to the v-drive with a double guibo equipped driveshaft using the 96mm guibos instead of the weaker 93mm ones like i used.
the transmission / vdrive driveshaft would probably be torque tube style to align the flywheel. that worked really well with the goldwing box.
I think you're right about retrofitting the MR2 cables with a solid linkage. The only thing that concerns me (other than time) is that the solid rods wouldn't really want to accommodate the to-fro rocking of the engine. I dunno.
the stock MR2 has a left-right motion restricting rod on the driver's side top mount. the motor should never shift left/right so i'd just go to the rear firewall with the rods and into a bellcrank that makes both rods go left/right from these those rods could connect directly to the transmission. the stick in the cab would likely vibrate with the engine a bit, just like a longitudinal stick would but it should be crisp.