Dude !! Awesome !! .. Love to see people doing real work to their cars !!
i'm sure gizmo will give u a reply in the week about the diff.. but i'm sure its gonna be best to swap rear subframe and such..
I think Uber Soldat has some narrows, i will give him a call tomorrow and see

he has more E34's than most people have hair on their heads.. lol.
btw, 525 motor will make a Huge difference !!
will check in l8r, need to sleep, gotta drive 2400km tomorrow :/