Hi Oakman,
I've stated the kind of sound that I want in one of my previous threads. A more immediate, involving, "life-like" sound is definitely one of them but not at the expense of clarity, transparency, imaging, authority, crisp timing, deep and well-defined bass, pinpoint acccurate soundstage, the whole works. And I don't think my current setup can give me all that. Perhaps not even the ATC SIA2-150. I may have to venture into pre/power territory which I prefer not to because I just adore one-box amps, don't know why.
Sorry that this thread doesn't give you the whole picture of my hifi adventure. I purchased my current set-up to use as a decent starting point that I can use as a reference point for future upgrades. So I'm not only looking at upgrading the amp but the speakers and source as well.