Pass Labs 1st Watt Rundown

I have become intrigued with the 1st Watt series and I am trying to wrap my head around the series and the differences within the series, but the internet discussions seem shallow.

Can anyone give me a rundown of the different models, versions, whatever?

What are the differences from one to another?

Did the newer iterations correct problems of the previous models and what were they, or did they simply address differences in power?

Stereo? Monoblocks?

What pre's and the sensitivity of the speakers you used with them.

Anything else you can think of as to characteristics of the different models.

Thanks