Nice matey
The problem with the back box, well the back box should be pointing down a bit with that one (Or so it looks to me, and thats why the tailpipe points upward, so...... hopefully when offered up properly it should clear the bumper.
Good luck matey, youll need someone to help you fit it because doing the decat -> manifold hook up its a two man job..... or youve gotta tape some spanners in place hehe