Burn-in complete and room correction rerun. Upgrade, inclusive of ID41, appears to be quite worthwhile. As others have noted, clarity is improved, as is low bass. The bass balance change I noted before has been largely remedied by rerunning room correction, although I have found it necessary to back down a bit on the amp that runs the bass towers in my main speakers. I also find, curiously, the need to select a slightly higher width setting on Trifield (1.3 rather than 1.1). Can't really explain that one.

The best barometer for me for an upgrade is to play something I'm familiar with, think I hear something amiss with a tweeter in one of the mains, only to realize it's a recording flaw I've never heard befor. This has happened twice today.

My Kit: 861v8+ID41, 800v4, UHD722, MD600, MS600, MS200, Oppo BDP-203, Genesis 201, Genesis 350 SE, Genesis S4-8 Sub, BG 520i, VTL MB450 II, Krell Showcase 7, Genesis 928 Subs, Danley DTS10 sub, SVS Ultra 16 subs.