Happy new year everyone! May I recommend getting a sub before you do anything else? I own the A8s and used them for a couple of monthes before getting a UFW-12 from AV123. While the A8s sounded great by themselves, the right sub will add a 'foundation' to the presentation that you juat cant appreciate until you hear it. My preference is to crossover above the natural rolloff. What I have found is that by relieving the B200 of its low bass duties, and impedance rise, even greater dynamics and less distortion is realised. Another advantage of this is that bass modes for the A8s are lessened allowing for better placement for imaging. I do know that many disagree with this approach.
As for the OB vs the aperiodic loading, I came to the con conclusion a few years ago, after owning a pair of Magnaplanar Tympani IDs for many years, that the bipole presentation, while captivating and exciting, did not give as pinpoint an image as I'd like, and was very sensetive as to placement and sweet spot. This is, of course, highly subjective and only you can make the final determination as to which presentation you like
better.