Wilson Watt Puppy, which version?

I am thinking of getting into the WIlson line with the Watt Puppy's. I have heard a few before in showrooms and I enjoyed them. I can not afford a new one, so looking at the previous ones there were several versions produced over the years. Can anyone explain the differences and if there are any "sweet spots" in the line up. ie is every newer version better or was there a point of diminishing return with the introduction of newer versions? I am trying to stay under 10k for a used pair. Thank you
I never liked any of them until the 6 and 7. To my ears, the 3/2 was a painful listen and the 5.1 wasn't much better. Things changed with the 6 and 7 which are two of the best speakers I have ever heard. In my opinion the 8 was a step backwards and, if memory serves, it didn't stay in production as long as the others. I actually prefer the iterations of the Sophia. Good luck with your search.

Vdosc...I would go with a Sophia 2. They are easier to drive and probably a better match for your ARC VT100 Mk II than the Watt Puppies. You should be able to get a used Sophia 2 under $10K.
I agree with Narrod. I think that up until the Sasha, the 7 was the best Watt Puppy.