I recently purchased three RF7iis for my LCR in my HT set-up and I was on the fence on whether I would see much of a benefit from the addition of an external amplifier as opposed to powering them with my pretty competent Maratnz SR7005 given the high sensitivity of the Klipsch Reference line.
Boy am I glad I went with an external amp! The RF7ii are a completely different monster with my Lexicon CX-7! It is a night and day difference and I do not even listen to them anywhere near reference level. It was as if I had been listening to them with a pillow wrapped around my head when using the SR7005 as compared to the CX-7. The external amplifier really brought these to life!
Just thought I would post my experience should anyone else find themselves in the same boat I was in!