@slaw honestly not on a lookout for one so can’t say. To share my experience…
At the time I owned B&W N803 driven by a DNA0.5. Upgraded to DNA-125, loved it so much and needed slightly more juice for the N803s, I sold the 125 and picked up a mint DNA-225. That amp was everything I was looking for, sound and power wise. Just totally gelled with then rest of my gear (ARC LS-15, ARC CD-3MkII). But the upgrade bug bit. I sent the 225 in for the Gold Revision. When I got it back it sounded pretty much like a different amp. Long story slim, the synergy was no longer there even after the extensive break in (300+ hrs). It just didn’t work out for me. The sound was fatiguing with heavy presence region. I actually preferred the sonics of the stock 125 over the modded 225. I ended up selling the 225 and in the process took a decent hit. The market at the time (2006) was flooded with modified McCormack amps. I saw my amp on the market few more times shortly after, changing hands.
I ended up picking up a mint Pass X250.5 locally and was back in the listening chair with a smile on my face.
So what I’m trying to say here is if one is looking for 125 to mod, go straight to 225 and just enjoy the music because that amp is truly special. Don’t bother with mods. CJ did a super fine job with DNA series amps. The 225 just makes music…bottom line. The stock 225 is one of the components in my audio journey I regret getting rid of. It was that good.
Now, YMMV and I won’t argue. Just sharing my experience.