Back in 2008; I purchase my 135I from Tischer BMW in Silver Spring, MD.
I was also utilizing the USAA no haggle price. None of the local dealer in the DC area were helpful at all. My Sales man at Tischer was Sigis Skirpa and he honor USAA pricing without a single problem. He went out of his way to find a local car with the exact options that I want on it.
Also they were the ones who gave me the higher trade in value for my 2005 Porsche Boxster at the time. I am currently in Afghanistan and pre- ordered a 2011 X3 for the wife before I return home; My dealer of choice for US delivery in the DC area will be Tischer no question ask.