Well in terms of strength, both transmissions are going to be about the same. Im sure the bearings are the same, possibly slight ratio alterations? or wider gears maybe? Maybe its stronger like a G54 is to a G52. I'll have to ask Marlin...
If you use the W59 however, then you will have to use our MC09 Taco adapter to convert it back to a gear drive transfercase, or you would have to swap in a drivers side front diff
which would have to be some dana as Toyota never made a driversside 8" diff.
KISS - Keep it simple and stick with a 85-88 or 89-95 style W56 + t/case setup and use the bellhousing from a W59. Now since you already have a W59, you could change the output shaft and the tailhousing of the trans to make it compatible with the gear drive t/cases..
