The BL11 is stealing sales from the BL2 around here, and I must admit that the BL11 is pretty impressive - leaving the BL2 for those that need a home movie theater, I guess. The best thing to do is to test the BL11 at home - ask your dealer for a home test.
Regarding the BL9 vs BL8k/BL2 - the precision offered by the BL9 and the detailed high-end and the fact that you have two sub's (on in each speaker) makes this option a no-brainer IMHO. I have both the BL5 and 9's, but do think that the BL9's are the best value for money speakers currently on sale by B&O (next to the BL4k).
Roger