Any thoughts on Great Northern Sound mods?

GNS sent me an email in response to a question I asked them about mods to my Timbre TT1 Dac. They said they would love to look it over and write a proposal. I'm just wondering about peoples' experiences with their modifications. Have the effects been positive or negative? Or perhaps they've been both. Either way, I'd like to hear what you have to say.
Steve Huntley is wonderful engineer. However, why in the world you want to upgrade TT1 via NOT Timbre Technology (215/540-0805, David Goldstein). You sure you have the latest upgrade of this DAC?
Steve Huntley worked on my Audio Research tube amp and performed magic with it. It is by far the most musical amplifier I have ever owned. It started as a typical older ARC sound and is now on a level with their current offerings. His attention to detail is first rate and he really seems to know what he is doing. I checked into his background prior to having my mods done and found nothing but favorable recommendations.
Pugsrub: Steve Huntley is wonderful engineer (and person too) and you ellaborated on the example of Audio Research (where he worked for many years and know their equipment very well, BTW). If Timbre Technology would not offer constantly upgrades I would join you advice without any hesitation. However, why do you think that David Goldstein and John Kukulka upgrades on their own equipment would be inferior to that of Steve?