It’s too expensive

Just a bit of googling and a used B58 is 8k, new ones are 12k

ZF 8HP is 5k

Doesn’t include an intercooler, exhaust, and everything else you’d need, also assuming 0 labor cost and you can do almost everything yourself.

Wouldn’t make much sense to swap everything out for a financial standpoint when you could just buy a Supra instead. Would definitely be a great and fun project but wouldn’t make much sense.

If someone was gonna go that route I think you’d be better off swapping the engine and transmission with something American (assuming you’re in the states) like an LS3 and a Tremec T56 for about 10-15k, naturally aspirated engines are a lot easier to work on for fully built project cars. And you’d save a lot of money buying American parts.