I will be taking delivery of my new bronze 2011 X3 on Tuesday. I'm thrilled; however, I'm buying the one off the lot and it doesn't have a hitch. We like to bike ride in my family and have a four person bike hitch on my current car. Should I purchase an after market hitch or should I purchase the BMW dealer hitch? Any thoughts? Price differential? I also received a $500 accessory credit with the dealer. I know I need a cargo mat, but any other accessories you think would be fun/needed/useful?