This is not a how to, but reading it might alert you to some things you didn't already know:
http://www.bimmer.info/forum/showthr...t=22629&page=3
If you do find a parts list and or instructions somewhere, it would be cool to know exactly what's involved.
My vote is for swapping the S52 and transmission into the Touring. Even though the 318 would haul ass, it can't haul much of anything else...