No such thing as an SW20 tranny.... but I'm assuming you mean for a turbo. If you are planning on doing a swap... look for a half cut. There are a few shops in the LA area that have them.... but none of them ship. I think the shops are selling them swapped though.... like... you have to pay for the labor to get the engine. Probably a little out of the way for you. Most places on the internet have their horror stories... so I'd be careful. Try
http://mr2warehouse.com ... I think they had a couple 3rd gens come through.