I have long been interested in the Judson Supercharger, and thought they were one of those cool, but out of reach, period accessories that would be great to have. I have learned a few things about them over the years but am by no means an expert. I remember reading an article in a contemporary magazine a few years back, and they did not add 50%, as was often claimed, to the power output, I don't remember exactly what, but maybe something like half that or a little less. Second, I had a car buddy who had a Sprite that had one, the vanes are some sort of treated fiberboard or plastic, they are held against the outer surface of the supercharger by centrifugal force, that is why the had an oiler to constantly feed Marvel Mystery Oil into it, the guy was an ex British Leyland mechanic from back in the day, he felt it wouldn't last long in the best of circumstances.
I still think it is a cool period go fast piece, but maybe better for the show field and occasional pleasure drives than something you would want to put in a car you drive on a regular basis. I don't know what a good price is, but they are not very easy to come by.