Just FYI,
My dealer wanted almost $300 bucks to buy and install front and rear mud flaps on my new 2008 X5 ... (crazy) Took me an hour to install all four. Hardest part was getting out the original plastic fasteners. In hindsight as they are not reused, I should have just drilled them out.
Taking off the back wheels a must as far as I'm concerned and come the time I need to change the tire I now know the routine.
Save the $175 bucks for installation ... do it yourself.
Mike
BMW instructions in PDF (3 MB) can be downloaded at:
http://www.lunacreativedesign.com/mud.pdf