If Steve McCormack's design is anything like Nelson Pass' (and why wouldn't it be) it uses active autoformers to match input and output impedances, but the rest of the circuitry is passive. Firstwatt has that pre, and recently released a DIY kit with the JFETS for like $50.
Regarding the KX-R, it was rather the toast of the show. Impressive, considering the issue of Stereophile hadn't come out yet, and the deep pockets were just carrying their "recommended components" issues.
Insofar as I can describe the sound of a preamp in various setups, I would say it was extremely transparent. Soundstage is difficult to capture in a hotel room, but every room I heard the Ayre in had far better than average depth, width and height. That's understandable with the Vandersteens, but I heard the Ayre in the Lansche / Continuum labs room, too, and that room took best of show in my book. Timbre was dead accurate, noisefloor was absolutely zero, and the size of the image was phenomenal. If you're in the market, you should really go for a listen.