It seems like we were in the same boat. I would recommend you to try out a tube preamp instead of changing out the MC352. I love my MC352, it is absolutely musical (my next upgrade maybe a MC501 or MC602). To get the type of three dimensional, harmonic rich sound that will draw you to the music; I have finally settle down with a BAT VK51SE preamp. I have the Levinson 380S preamp in my system for a few days. Nice but it did what you described, lots of detail but it did not draw me to the music. Then after a few more extended home auditioning of quiet a few other respectable preamps including BAT VK31SE (VK51SE is much better), Spectral DMC-30S (great combo by the way, after listen my friend like it so much he brought a MC602 to replace his existing amp), ARC LS25MKII, ARC Ref2 MKII, VTL 5.5, VTL 7.5, and each reproduce a certain aspect of sound better than the other except the flagship model from the same company is always better than the lower priced model, figure that!. It was a difficult choice for me. Bottom line is it all comes down to personal taste and I picked the BAT VK51SE and I have not regreted it since. Now I listen to music till 2 to 3 am in many many occasion, I felt like I was addicted. Try out a few of these preamps and I think you will find what you are looking for. If you want to take another huge step to further improve your system. Get a Virtual Dynamic Nite power cord and put it in your MC352, it is magical! A huge improvement. Mcintosh Amp love this cable, my friend who now own the MC602 and the Spectral DMC-30s combo has his jaw dropped to the floor when he heard the improvement of his system using this cable. Since then I wire my entire system with the Nite cable and my system is now sounding incredible. It has everything you describled about harmonic richness, three dimensional, and present but now it just has more of it. Good luck with your search, it is a fun journey.