Hey Dusty. Great find on the Mac. I run MC40s and recently (today) added a Conrad Johnson PV-10A preamp and am very happy with the upgrade. I have only listened for a few hours, but I can tell this thing is a very musical and clean sounding pre, and I haven't even checked out the phono section yet, which I have been told is very very good. Just something you might want to consider.
Very nice system you have. I bet it sounds great.