I just got my 2003 4.6is back from the installer, where I had the M3 steering wheel with paddle shifters installed. You can read about the steering wheel and see photos at:
http://www.xoutpost.com/x5-e53-forum/...ghlight=paddle
I won't rehash that information -- I just wanted to report that this is a GREAT mod! I'd swear that it is FAR easier and smoother to shift manually than with the regular shift-knob in S mode, and I'll be shifting manually a LOT more often as a result.
The steering wheel itself is a bit smaller (in diameter) and more heavily padded than the stock (non-heated) steering wheel. It's a different feel, but I actually like it better than the original! I can highly recommend this mod!