i don't see a reason why the USDM motor/tranny won't bolt right up. IIRC, the wrx wagons has the same track width as the GC8s. that means the crossmember should bolt right up. if not, i am sure there's other way to get around it.
BAIC member EddyRS is doing this swap right now (of course with the help of Skywalker and Chris), so maybe you want to check that board from time to time.
BAIC member EddyRS is doing this swap right now (of course with the help of Skywalker and Chris), so maybe you want to check that board from time to time.