I believe the tunnel has to be modified. A BFH is what is used for that. Other than that I'm not sure. There is a write-up somewhere. I'll see if I can find it.
i dunno bout that, theres a place that sells the T56 swap and i think its 2500 for the Tranny, custom driveshaft and tranny brace/support. maybe call them and find out what is needed and the procedure.