9rw, yes, I am a Nuforce and Legacy dealer but I'm also an enthusiast. And though the Aerial 10Ts would hold their own against many speakers, the ribbon tweeters and ribbon midranges on the Legacys provide a more complete and refined musical presentation than the Aerial 10Ts and perhaps many other dynamic-driver speakers. Amazing how much more complete horns, vocals, and strings sound. And the 10Ts were never a bad speaker in my opinion.
BTW, you never did expand on your experience about what you heard specifically with the Nuforce amps. In fact, your comment to Ggil almost sounds as though you never auditioned the Nuforce amps. I hope that's not the case.
Nevertheless, based on the system you listed I would like to take a stab at some comments and suggestions as to why I think you may be hearing 'zingy' highs in your own system.
Speaker Cables and Interconnects
I would recommend auditioning other ics and scs. I've never heard the Cardas in my own system but I've heard them in others and I've heard what others have compared them to and based on that information I would not hesitate to audition other ics. Seven years ago, I owned both the AZ Satori (shotgun bi-wire) and Harmonic Technology Pro-9 speaker cables (both engineered by Robert Lee of AZ). In my experience the Harmonic Technology Pro 9s and AZ Satoris were loaded with time-smear as are many cables. But that only became evident when I replaced them with the similarly-priced Audience Au24 speaker cables. Even better cables are the Paul Speltz Anti-cables and Anti-ics, Balanced Power Technology, and Audio Tekne cables. But the Audio Tekne scs and ics are far better than any of these and are almost identical in price. I still am not aware of a better ic or sc. Installing any one of these other cables could easily minimize the so-called zingy highs that you claim to hear while also providing much greater bass definition and a far more musical and pristine presentation.
Line Conditioning
I've heard good things about the Audio Magic lc, but it sounds like you have no line-conditioning for your other components. This is a big and obvious area of concern and could make any revealing component sound weird in the highs. Any component that is not receiving proper line-conditioning is passing much AC noise into the presentation. One of the most obvious side affects of improper or no line conditioning is negative sibilance and the affects can easily be interpreted as zingy highs, fatiguing, etc..
Vibration Management
To the best of my knowledge there's near zero if not zero performance gains in the Target rack and perhaps just a bit more performance with the BDR cones. In either case if either one of these items has no performance value, then the other item will not be able to perform either because they must work together. This area of vibration mgmt may not seem significant at the moment but properly addressing vibrations can bring by far the greatest performance gains you may ever hear. If you've ever been in your car at a stoplight with some kid blasting his subwoofer two cars behind wreaking havoc on your car in the outdoors, you can begin to get an understanding of the absolute havoc caused by vibrations trapped inside your components in a closed-in room. Obviously Robert Harley (editor of The Absolute Sound) is not aware of this fact, otherwise he would never have admitted to auditioning the lightweight Nuforce amps by placing them on the carpet as he claimed in an issue about 9 months ago in TAS where they systematically tried to pooh-pooh all Class D technology in general and essentially retracted their Nuforce amp the Amp of the Year award. Still Harley said that he enjoyed the Nuforce amps. But when Jonathan Valin claimed that all the Class D amps just sounded weird in the highs makes me think perhaps he had his digital amps hanging from a chandelier. At the very least you could audition Star Sound's Audio Points. This may only get you about 5 or 10% gain simply because of the rack you are using. But that's still a pretty good and inexpensive improvement and would help minimize the so-called zingy highs you claim to hear. To realize more benefits, you would have to replace your rack with a performance-oriented one.
In summary, any one of these deficiencies will make any truly revealing component sound fatiguing, 'zingy', hyper-detailed, etc. I can all but guarantee that if you or anybody else (including TAS) claims that weird things are happening in the high frequencies with the Nuforce amps in place, it's simply not the amps. Rather for the first time deficiencies within the system may be exposed because of the extremely revealing Nuforce amps.
Bottom line is a truly revealing component is not so common in high-end audio. And when such a component does come along its revealing beauty for what it does with music also becomes its own worst enemy simply because a truly revealing component must be indiscriminate about what it's revealing. Whether it's musical information, time-smear, AC noise, or trapped resonance energy.
But then again, it's all too common to shoot the messenger.
-IMO