I have a friend who owns a machine shop and noticed my visits there he deals with aluminum a lot. I'm thinking that would be the place I will score the 1" thick aluminum. Now I have looked underneath the car and see nothing that would cause trouble going backwards 1". The only thing I see that is questionable (kocuda can answer this) is the drive shaft yoke coming out of the trans 1" further back. I'm guessing there is plenty of yoke to output shaft contact still left but that's all that seems questionable for me.
Yeah pictures please!