Well the simple solution to shipping twice is to have your seller ship directly to Dan for the Signature upgrade.
Regarding performance of the Signature. I don't think I can derive succinct comparisons to the standard model, because my audio memory isn't that good (although Dan did turn it around in under 2 weeks, door to door). He also updated some of the caps from Sonicaps to his new house design, so there is an additional variable.
So, I hadn't planned on posting on my happiness until I had some more time with the Signature, but since you ask... My impression is that the delivery is smooth and effortless, and just a bit rounded. Rounded is not an adjective I considered before, so I'm guessing there is just a bit more euphony from the Signature. Yet, the musical detail is still there on all my reference recordings, and this would seem to be the best of both worlds.
I had previously experimented with tube dampers and eventually settled on not using them, but I'm planning on trying them again as I become accustomed to the new sound. For reference, I am running old stock Tung Sol 5687's. Now, it's quite possible the new caps have not completely broken in. I haven't seen much commentary from Dan or others on what his branded caps do better or how long they need for stabilization.
The build quality and layout of the new power supply board is just beautiful. Almost inevitably when I see a piece of equipment and the power supply is more complex than the audio circuitry, it's an excellent design.
Yeah, I ride, but not nearly as much as in years past. I used to be a Kawi guy - GPz550, GPz750, Ninja 1000 (ZX1000R), ZX10 (the original), ZX9R (the original). Then I went for the Suzuki TL1000S (as evidenced) and now a Ducati S4R. Twins are where it's at
Tim