Hi James, I don't believe there's an MB2 '+', so I'm thinking you must have acquired the regular MB2 speakers.
I would in fact be quite interested in hearing about how your speakers respond to different combinations of amps. You obviously have access to a far greater choice of amplification than the average user.
Activation would of course be the best way, but how would you go about it? Btw PMC use am 875HT amp for their regular MB2A, and I'm also interested in seeing if a passive with the new bigger square amps will approach the performance of the Active with the old, smaller 875.
Please let us know your thoughts once you've received the speakers.