as someone mentioned above - Ebay has several BMW dealers that sell the OEM paint with free shipping... I got mine from a dealer in New Jersey.
If you have a lot of chips or pitting on the bumper or hood (road rash) Dr Color chip is supposed to be easier to apply to a larger area since its dab + smear.
If you have more minor chips or chips that are deep... OEM + Langka (
www.langka.com) is supposed to work better since you can build up layers of the OEM touch up paint better than the thinner Dr Color chip paint.
I did a few chips on my hood with the OEM paint + Langka ... this combo worked well for me.