Steve McCormack and Patrick at SMc Audio have upgraded a pair of my DNA-1s, a large DNA-2, and a TLC-1 preamplifier that is very close to what you get from his highly regarded VRE-1. In short, the upgraded preamp and DNA-1 monos are very, very good sonically, IMO. I compared the preamp to around 20 other preamps, a couple of which were north of $10K and I have not found anything that sounds as enjoyable to me based on tone, body, clarity, and dynamics. Same with the DNA-1 monos. While those monos may not be the very best at any one thing, they are quite good across the board with the end result having excellent tone, body, clarity, dynamics, and drive, and no noticeable shortcomings which, IMO, is a rare and welcome attribute.
Regarding upgrades, all they need now to create an upgraded amp is a unit that has intact chassis and heat fins, because they can replace virtually every other part of the amplifier in their new builds, including the boards. The amp you send them doesn't even need to work. If you can sell your amp for a little more because it is a Gold revision, you may consider selling your amp, buying a DNA-1 that has not been upgraded or that may not currently work, and using the delta between those transactions on the upgrades.
I suggest researching the current state of the upgrades further on their website where there are some youtube video interviews with Steve. I recommend looking at videos 3 and 4 for more info about the amplifiers. You should also check out the new amplifiers they are offering. I am very happy with my upgraded amplifiers (pictured below) and IMO they sound overall better in my system than the Clayton M300 Class A monoblocks and the Lamm M1.2 Reference monoblocks I owned previously.
