That's a decent price for the KG 3.2's.
Not sure which model Infinity SM's those are but my experience with the SM line is not good and would probably never look twice at any for sale. The SM's in your photo look like the better higher end versions so they may be ok. Hopefully someone with experience in that particular model will chime in. Refoaming is like other speakers. The cones are plastic and not brittle like some of the poly materials used in other speakers so it should be fairly easy to do.
I would buy the Klipsch 3.2's.