This was a fairly effortless swap as we didn't have to reinvent the wheel. We purchased engine mounts and headers from Vorshlag.
Although we did have to fabricate a transmission mount as we were using a T56 rather rather than the stock ZF.
Zero mile 525hp create LS3 engine ready to go
Trans bolted up
Boom, installed in the car
Welded up some V-bands to mate to the headers
Built a trans mount that tucks up tight
Mmmmm...much better than the S54