Thanks for the input folks!
Yes, I just tried turning off the up sampling and while it adds lots more high frequency emphasis to the sound it robs the sound of warmth and harmonic texture, making it sound a little grating and harsh. This must be what added jitter sounds like...interesting.
I will definitely look into your suggestions if/when I head down the upgrade path in the future (and save up lots of money - this Sooloos and Meridian stuff is not cheap

Meantime, any other suggestions to get the most out of the MC200 at minimal or no added investment would sure be appreciated!
Cheers,
Kerry