Ask over at the Infinity owners forum at the AudioKarma site. There are lots of Infinity fans there who can give you good/current advice on price and what to look out for.
BTW, I own a pair of Infinity RS1.5s and Qbs. The 1.5s are excellent and the Qbs are also very good. I pair $264 USD and $116 USD respectively for them within the last few years.
