Well, I've only owned, wrenched on, and raced BMWs since 1983, so I can't possibly know as much about them as you; after all, you have a friend who owns one.
Again, anyone who actually needs FWD or AWD to drive in the rain should do everyone else on the road a huge favor and start using public transit...
The FWD and RWD is a safety issue, just going around a turn and tapping the gas a little too hard can throw the rear end out.
So when you replace a part on your BMW, is it not 3 times more expensive for that part than lets say a mazda? At least, that's what I've seen the ballpark to be, about 3 times more expensive.