In reply to:

I suppose M2i + STF-1 would be the way to go, since B-stock versions would cost just under $500 USD.

Pairing up the M2i's with a good sub is a magnificent combination. Looking at both the M22ti and the M2i frequency response graphs, everything above 80 Hz looks aproximately the same (as opposed to the tipped up midbass and treble of the M3ti).