Sudesh has a lot of info. on the DIY and different wheels check out his link here...
http://www.xoutpost.com/x5-e53-forum/...ring+wheel+DIY
I did this mod last year and love it! Its one of the best mods you can do to the X IMO, many say that the E46 M3 wheel is one of the best factory steering in production and I have to say I agree. You can also purchase larger paddles from a variety of websites, I have not upgraded my paddles yet but I have been thinking about it. Good Luck.