high end speakers? ... not sure what brands/model

You need a 'horn' experience. If you have not noticed, many of the high end speakers are horn's. If you have the room, think about a vintage Klipsch pair, great sound, great value.

your amp and speakers are better than 90% of consumers gear. Achieving sonic bliss will be expensive as you chase that elusive 10%. If you are happy leave it alone if not audition better gear but be prepared to pay.

They seem a bit heavy on the high side. I want it a bit richer in the low end ... smooth bass, etc.
They do sound nice but, seemed to sound better in the shop.
Perhaps it's mostly my room. Can't mod the room too much, it's our formal living room.

Maybe I can add a sub.

Rob

Disagree completely with the horn guy. Horns are interesting, but vintage klipsh speakers are far from neutral.

Based on your last comment, I'd try Dynaudio. The have rich bass and a smooth treble.

I apologize for not proofreading my initial post. I meant to say that "Your speakers are definitely ABOVE average in the grand scheme of things, as is your amp." You have a nice system that bests that of most people, and uses high-value components.

I'm not sure what you mean by wanting more "richness" in the bottom end. Do you mean more bass weight? If so, maybe your best option is to add a subwoofer to shore up the low frequencies.

Take your time, and try to audition speakers in your own room, as that will give you a much better sense of how they will perform in the context of your system and room.

Michael