Do Pass X-Series Preamps Match with X or X.5 Amps?

Hi everyone,
I was just wondering whether the Pass X-Series preamps such as the X-2.5, X-1, etc., match up best sonically with the older X-Series amps such as the X-250, X-350, X-600's, etc.,or with the newer X.5 series such as the X-250.5, X-350.5, X-600.5, etc.?
If you have tried or heard them together, please describe the differences.
Thanks a million!
I owned the X-250 and X-1 preamp and they worked really well together. I also came to realize that the X-1 was a really good preamp versus a bunch of others that I tired. I also found that the X-250 worked well with any active preamp I tried tube or SS. The best preamp that I mated to the X-250 was the Tom Evans Vibe. That preamp was something very special. There were a few tube preamps that really added that nice tueb mid range to the X-250 such as the Blue Circle B-3 MKII and older Counterpoint SA-5s & 5000s. I also did not find a really big difference between RCA or XLR cables, the XLR offering a quieter background and slightly better clarity and details but not worth changing all of you cables for.

Happy Listening.
I have an X350.5 and both an Audio Research Ref 2 and a Pass Labs X-0 preamp that I use to drive the amp which mates with a pair of Avalon Ascents and a REL Stadium 3. For most music I prefer the Pass Labs over the Audio Research. Violins seem to have a better decay effect with the tube preamp, but female focals are clearly more musical with the solid state combination. I have owned many tube amps and I wouldn't trade any of them for the X-350.5.
Happy listening.
Any further thought in the Pass Preamps for use with the XA amps, versus tube pres (I own a Joule LA 150 MKII whci drives low impedance amps well - the Joule amps themselves are a lowish 20 kohm input impedance)? Another way of looking at the question might be: Is there anyone who traditionally used and preferred tube amps that has decided a Pass pre was the way to go?