Synergistic Research Tesla Users......

I believe D2 and D3 are active shielded.

Your dealer is incorrect, at least in my experience and your guesses are way off. In my system, the D-3 bested Mexcel Acrolink cables costing more than twice its price, as well as every other cable I tried. It is the best digital cable I could find from my transport to DAC at ANY price. Yes, it is THAT good! You get what you pay for with the D-2, which is a good cable. With the D-3, you get world-class performance.

Is it worth the money? In my system, absolutely. Do yourself a favor and demo a D-3 for about a week. Maybe from a different SR dealer ;-)