Tim,
I’ll toss a couple of minor suggestions. I really liked my room as well and didn’t think I needed anything more. I attended the Capital Audio Fest in the Washington DC area last fall and heard a room with Vicoustic Multifuser DC2 panels between the speakers on the listening wall. I was taken at how focused the center sound was. I got 6 of the 2’x 2’ panels for my room and it didn’t change the sound, but really improved the focus and imaging. Vicoustic is European based I believe and huge there.
As to cart choices, I saw a recommendation for the Lyra Delos. I have had that cart for a few years and really liked it’s precision, but I have since added the Audio Technica ART9 to my stable, and and Delos is now sitting on the bench. The ART9 is half the cost of the Delos. It sounds pretty similar in tone, but it has a much bigger image, better separation, and is less hi-fi sounding. I suspect the ART9 would sit well with DL-103 owners.