Jman66,
I can tell you that the FET output, hexfreds, and Auricaps aren't going to make a significant difference between the stock units. However, the TRL modded unit will outperform the D1 and although I haven't heard it, I'm confident will also outperform the D2, both by a wide margin. I asked TRL if using the newly upgraded parts would add value to their mods and they were pretty ambivalent about it. In fact they were pretty impressed with the stock caps in the D1 and were confused why Vlad would go with Auricaps. They didn't see the need to upgrade that area of the DAC.