Well your upgrade path could be an 818v1 of the reference series. That would still outperform the MS600. It could probably be had for similar amount of money of a model inbetween MS600 and 818v2 like you are asking for...
So the 818v1 did not have a built in pre-amplifier? I've looked online and that doesn't seem to be the case.
My point is that I'd love Meridian to make their best endpoint technology available for MDMS owners who don't need a pre-amp or CD player. Right now it's like needing to buy a package that includes a bunch of stuff you don't need in order to get that premium stereo in a new car.
I appreciate that you're trying to give me suggestions on how to improve the sound I'm getting with the Meridian equipment that exists now, though. Thanks for that!