Klipsch La Scalas or Polk SRS 1.2's?

The La Scala's are an efficient pair of speakers your Adcoms should have no problem driving them. As far as other choices well the Polk's are a good choice, they are going to give you more bass and while less efficient than the Klipsch, the Adcoms should do a good job. I would say that your room set up is going to play into your decision if you chose between those two pairs. If i recall the Lascala's like many of the horn speakers are designed for placement in or near corners. The Polk's are optimally a more center (away from the sides) and away from the front wall. Since you had a set of JBL 100 LT's and are looking at similar vintage Polks or Klipsch do I take it you are a vintage American speaker listener or just a vintage speaker listener? If the former I think you have picked some of the better models. If it is a the latter I would tell you to consider the KEF speakers of a similar era, the KEF 105-2, 105-3, and 104-2.