I'll be doing it the hard way and modifying the existing firewall. ;) got the old unit out yesterday just some minor stuff to remove now and I'll start measuring and cutting Friday.
Also, a heads up, if you're in need of a gasket rebuild kit for the box, Detroit Muscle Technologies is offering up a new expanded kit which includes clips and the drain tube now. It's a little over $100, not listed on their website yet, shoot them an E-mail or call them.