Pass First Watt models ... confused

I'm curious about the First Watt products. I'm a very happy owner of a Pass x250.5 AB amp but interested in experiencing full class A. No plans to sell my less than 1 year old x250.5, and I'm not rich so I won't be sinking cash into the exorbitant prices of a new XA series. A used Aleph is a possibility, but those are getting fairly old and I wonder about maintenance issues.

Therefore I am looking at the reasonably-priced First Watt line from Nelson. But I'm quite confused by all the different models. Can anyone help clarify this puzzle for me? Thanks.
This is very thoughtful and reasonable feedback. Thanks and I will read up on them. My speakers are the older B&W Matrix 803 series 2. 8 ohm speakers, 90 db sensitivity. Keep the feedback coming if anybody has anything to add.
I've owned the Aleph 3, 30, 60s, and 2s. And an X150.5.
I also owned the Aleph J2. It sounded good.
I bought an XA-30.5 from a friend, recently.
For the money, I like the XA-30.5. It's true Class A, and it will drive almost any speaker, for a little bit more money (used) than the current First Watt amps.
So....What are the acceptable parameters for speaker sensitivity for these amps?
Al has it right; most of these are special purpose amplifiers, and you would be wise to carefully read the manual for each before purchasing.

Also, if you call Mark at Reno Hi-Fi, he can help point you to a suitable model for your setup, if one is appropriate.
"I also owned the Aleph J2. It sounded good."

Did you mean the Aleph J or the First Watt J2?