Well, after getting the unit home (I bought it used from a local retailer in Seattle, Hawthorne Stereo - thanks Matthew) I just HAD to open it up and see..
Damn nice! High-end epoxy circuit board, nice components, etc. Not much for power supply bypassing around the discreet transistor output stage, though. And alot of 'lytic coupling caps, too. Also, the PSU for the audio stage doesn't have active regulation, just a simple shunt zener "regulator". But it sounded so much better than what I was used to that I let it be... for a while. I can never just leave it be.
So the first mod that I wanted to try was to increase the PSU bypassing on the output stage and install polypropylene bypasses around the output coupling capacitors. I had some 1uf Electrocube poly's for this, and ordered my favorite low-voltage electrolytic bypass caps from Mouser. These are solid organic polymer electrolytic that have very, very low ESR and will never 'dry out'. I use them for cathode bypass in my tube products.. they work great and sound great.
Carefully, I removed the 4 polyester .1uf bypasses, installed the 100uf 16V (Vishay 94sa107x0016epb) organic polymer caps, then re-installed the 4 polyester caps to the underside of the circuit board, along with the 1uf Electrocube output coupling caps in parallel with the stock electrolytics. Now I put it all back together and didn't have any leftover screws! Yay!!
The caps needed to break-in so I let it play in repeat for a day or so, and then listened to my favorite evaluation disc, YES Talk (1993- killer dynamic range and lots of recorded detail). There was an improvement in dynamic slam and a sweetening of the high-frequency details. The bass is tighter and more textured and at the same time goes a bit deeper. Overall an improvement... maybe I'll leave it alone for a while. We'll see...