Pass Labs Amplifiers - XA160 versus X600

Has anyone ever compared these amplifiers' sound quality? I ran across this review on the Pass Labs website I found this to be a compelling review - especially given that this guy intimately knows the sound of one of the greatest orchestras in the world - the Vienna Philharmonic. So compelling in fact that I am tempted to run out and buy the very system he uses...Any comments on the sound of these amps?
Kmccarty, there's a pretty strong consistency, among Nelson Pass fans, that in the X-series the 250 was the best single chassis amp sonicly and the 600 mono-blocks was the best sounding of all the X-series amps. However, their were certain fans of Mr. Pass's, including myself, that found the X-series lacking the "warmth/musicality" of the older Aleph amps. This has been totally corrected in the new XA and X-.5 series amps, they offer the "dynamics/speed/drive" of the X-series with the "warmth/liquidity/musicality" of the older Aleph series. Remember, if price is not a consideration, that the XA amps do not double down into lower resistence but the X-.5 amps do, therefore one factor of which amp to use either a XA or X-.5 would be on what type of speaker you are driving. For example, I drive MG-20r's so I use a 350.5 which was a better match than a XA-100's in my system. If your lucky enough to be able to purchase either a pair of XA-160's or X-600.5's you are in for a great treat either way. Hope this helps.
Thanks Teajay - other than the power differences, can you also comment on the difference in sound between the XA-160 and the X-600.5? Thanks.
Kmccarty, my hunch, since I never had the pleasure to audtion them against each other, is that the XA amps are somewhat "warmer/richer" sounding then the X.5 amps. All the X.5 amps sound closer to the XA series then the first generation X series amps. Remember, we are talking about a very similar sonic signature, just degrees of difference between the XA and X.5 series. So, if the price difference is irelevant, I believe it would come down to personnal taste and system matching for the best synergy. In my system the X-350.5 was a better match then the XA-100's. If you want post the rest of your system and I will give you feedback about what might be a better match. Either way you go you can't lose their all great sounding amps!