about the 318is thing too, they definately didn't all come with leather interiors. but thats neither here nor there. I know at some point i was told that a certain newer 5 series diff that was an LSD would work... i was also wondering where to get a new LSD once mine takes a crap. one thing i do recommend though is using redline gear oil ( for viscous limited slip) its has different friction modifiers added to it to promote lock up of the viscous disks. like night and day when i first put that in my car. (91' 318is)