i've seen this, the 10r80 is basically a drop in because you can use the explorer driveshaft.
the 6r80 needs a spacer or a driveshaft made.
the controller last i checked is ready for the 6r80 but not the 10r80.
i have a turbocharged marauder 600-650whp on max boost, built trans circle d triple disk.
I've been told because of the weight of the car the 4r70w will never last at that power level no matter what you do to it.