For what it is worth. I also have the M80's but I use the EP350 version 3. This is the new EP350 with the larger enclosure and larger amp. It is a lot cheaper than the EP400. There does not appear to be any transition at all between the M80 and the sub. The sub's bass is very clean. I use a ATI1202 to drive the M80's. So far I like the sub, having tried it out with 2 channel music, a Collective Soul concert and the old Robocop movie. Like Outlaw - Axiom also gives the 30 day trial.