Unless u have lots of money i would stick to chevy. a 350 or 383 will have alot more power than the supra. And u wont have to look around for adapters. like my insurance agent told me."keep it simple stupid" no offence.
i also have a 383 with th350 and 203 case. the 203 is not full time 4x4. the 203 is heavier . i make the conversions on the driveshafts. chev to yota. the combo works great and is probably the cheapest.
i would go with the 4.88s and not the 5.29s if u want to go with small tires at times it would be too low geared. And you will want tire speed for muddin. This is a mud site isnt it? But it also depends how much power you have.
i run 4.38s in my truck and have 38.5 boggers i wouldnt want to put lower gears cause i have plenty of power and i wouldnt want the rpms to be higher. im at 3000 rpm doing 55 miles an hour. a lower gear would be rediculous.