Well I've been listening to the Superlink mod (done to my NAC82) for nearly two weeks now and I'm very, very impressed. Rest of kit is LP12, Khan, Ittok, DV 20X2, Radikal, S'Cap, 135s and SBLs. I'm probably not the best in describing differences to sound but here goes.....
I didn't think the bass went 'lower' but it is more defined and 'crisper', Lou Reed's Walk on the Wild Side being an excellent example for hearing this improvement. Vocals are certainly clearer and more true to life with background vocals by DB, Ronno and the Thunder Thighs on Transformer really shining. The biggest difference IMHO was how it untangled more complex pieces so that instruments were separated with more 'clarity' (perhaps the wider soundstage that Andyl mentioned).
I was most shocked to hear DB's Blackstar had even more below the surface with subtle bass lines being more evident, definitely a big grin on my face when I played this LP. Playing DB's Starman again made me just immerse myself into the man's genius, I've never heard the ZSATSFM LP (72 1st pressing) so exciting until now. One of my latest LP's is Melody Gardot Live. The recording now adding to the intimate atmosphere so much that when closing my eyes I'd have sworn she was in the room, her voice so clean, deep and sexy sounding (to me anyway!). If you haven't heard this 3 LP set I urge you to.
Overall you'd be right in thinking I am more than happy with this modification (I did have it serviced at the same time even though it probably wasn't ready for it). I'd long been looking for a good NAC52 but for the price and risk decided against this route. I have heard a friend's 52 and it has always impressed me. Without evidence I'd likely guess that this mod has bridged the gap massively, and so for value for money the 'mod has it'. I'm sure if you played them side by side the 52 would still prove the better but now not as much. With the mod, listening to one and the other a second night I bet most people would be hard pressed to distinguish between them.
If you're sitting on the fence wondering whether to get this done, don't, just do it!
Many thanks to Witch Hat Audio.