The challenge for manufacturers using Class D modules from a few central providers is that they must still distinguish their products, and for a company like NAD that has always favored minimalist presentation, that can't be the fanciness of the box.
If it were me, I'd focus on cooling, and then brag about what a high percentage of the maximum output I can obtain continuously, using some entertaining and wholly unrealistic tests. Or add distortion that I think makes it sound better with the sort of music most people play.
If I introduced distortion not previously there, I would be up-front about it: "The stock Purifi Eigentakt module is arguable transparent and without distortion. But real listeners find truly transparent amplification to sound dry and thin with many of the recordings they play. The Rickophone Godzillamp uses a custom-designed first-stage amplifier that merges the transparency of the Purifi final-stage amplifier with the music-enhancing richness of sound for which Rickophone has been justifiably famous. Listen for yourself--bring your recordings that have the music you love but that seem to have been mastered to sound dry as dust. We conducted extensive blind testing to demonstrate that listeners prefer the richness of the Rickophone sound to merely transparent amplification. We don't deny our house sound like other companies, we own it."
Then, when Stereophile or ASR measure it, and reveal its slightly audible even-order harmonic distortion, we can say "Yup! But notice that our house sound does not come at the expense of added noise--the noise floor is still at -130 dB just as Purifi designed it, and still produces only 12 uV of output when not playing music--you'll never hear hiss out of the speakers just by turning the Godzillamp on. And, with our silent liquid-cooling, if you play modern compressed pop music at full output for a six-hour party, it's your speakers you'll be worrying about, not the Godzillamp."
These guys should hire me to sling their BS.
Rick "available but not cheap" Denney