The Cimbali Max Hybrid grinder, that Chris sells, produces much better grinds than the Cimbali Junior or its cogener, the Cadet, the old automatic version of the grinder. This is not to say that the Junior is a bad grinder. I have owned 2 of them plus a cadet, one of which I sold to a friend and the remaining cadet and junior repose in my basement, probably never to be used again. I used the cadet and the juniors for more than 10 years.
The Max is, without any question whatsoever, a world class grinder as regards the grinds that it produces. I would rank it on the same level as the high end conicals. The junior, on the other hand, is a very sold, good, 64 mm planar grinder with nothing else particularly to recommend it.
You can get a brand new Max from Chris for $760.75, delivered.
http://www.chriscoffee.com/products/hom ... /maxhybridA new Max is (in my view) worth at least 2x as much as a used Junior. So, if the Junior costs more than about $350, I'd consider it to be overpriced.
As regards the mods that the seller says he made, assuming they are as he has described them, they do not sound to be very important, although they may make it impossible for you to resell this grinder later, should you desire to do so.
ken