Are Dynaudio Contour 2 any good?

I was trying to find any info about Contour 2 and I could not besides the spec on Dyn's web according to which they are extremely inefficient. I wonder if this is their major flaw or there are others. I’m looking for an upgrade for B&W M 802. I love B&Ws midrange and bass but I hope to improve treble. I run them with CJ MF 2500A and speaker efficiency should not be a problem in my set up.
Thanks,
Alex