I appreciate everyone's willingness and eagerness to help and to be sure, I am open to logical and reasonable suggestions from one and all. That said, I DID purposely direct my question to Bachus because I was aware that he was unique in having (extensive) experience with both MACs and Mainstage. And also, although I agree with Don generally (buy new), in this particular case where I was only looking to do an initial experiment/assessment to see if this were something I'd be interested in making a permanent part of my studio, the cheapest RELIABLE course of action was what I was looking for (I'm notorious for NOT returning things, so minimal loss for me is always a consideration ). I will most likely go with the minimal USED machine that will run a full-blown version of Mainstage (without hiccuping). If I really, really like it, I would upgrade when future circumstances dictated. Part of the reason for going with minimal expenditure is that I have a number of state-of-the-art PC's for all my other computer-related chores, so this would be a single-purpose machine.

Again, thanks to all for your help and suggestions. SZ is certainly tops in that department. As I used to teach in my class on decision-making, the more the possibilities, the better the decisional process and the better the chance of a good outcome.

chas