I don't know what the future holds, however, today there are only 2 BMW's on the 2013 Barret Jackson's list (see attached image). I have a 1987 BMW 535is that car at the time of sale in 1987 was only one step below the then M5. Our 1987 does has the bumpers from the M5 and some other M5 options. I have no clue what the car would get at Barret Jackson's auction not that we ever sell it it has too much sentimental value.
In general I think there is not too much interest at Barret Jackson for European cars considering the overwhelming American cars at the yearly Barret Jackson Auction.