Ahh, very cool! The whole engine series is pretty great, honestly. 2K, 2K3 and XP are far more interesting than some people understand~
Honestly, there's not a huge difference between MV and Z. The biggest difference is that MZ is a more polished version of MV, just like how miniscule the differences between VX and VXA really are. At least that's what I've noticed when I played around with both of them; granted, I haven't used MV/Z as frequently as I have the older ones, so there might be more differences between the two than what I've noticed.