Also, there is a You tube video floating around that shows how to check for trans bearing wear -- basically you drain the trans fluid and stick a little finger inside the hole and feel for grease and shavings on the magnet near the drain hole. I'm just passing on second hand info -- but you might also want to check with "Tholyoak" in Kansas who has put several of these motor swaps in older Boxsters.
FWIW, etc...
Take care,