Pass Labs x350, x250, .5, thiel 3.6

... Which Pass amp would best drive the Thiel 3.6(x250, or x350)? Can I keep my Levinson 38S pre with pass power? I mean I know I can, but would the two mate up well? And which is most economical by A used pass amp, have it shipped to pass for upgrade to .5, or by the .5 serious new outright, from a pass delear, which may not be in my area( northern Chicago subs), due to the restructuring of autherized dealers.Thank you
Max pain, you cannot upgrade a Pass Labs X generation amp to a X.5 series. The .5 series is a significant change from the X series for the better. Read my reviews both on the 350.5 and XA-100's for more details regading the sonics of these wonderful amps. I believe a 350.5 would be a great match for your Thiel's and your ML 38S would work just fine with the Pass, sometimes you have to be careful with tube preamps with Pass power amps, but this mute in your situation.
I tried x350.5 & 250.5 with Thiel 2.4. They were very synergistic match
Yup not upgradeable and I would go with the 350 for the 3.6's.

Hmmm, I'm glad I posted. I thought you could upgrade. Once again AG'rs saved my butt.