You didn't give your budget but the Quartets are 97.5db efficient with an 8ohm impedance. From what I know of Klipsch the impedance doesn't represent just how low they will dip. You will actually want to use the 4 ohm tap more than likely. But the speakers are pretty efficient. I had a pair of Chorus II that are similar in basic design but more efficient than the Quartets. I would say, if you can swing it, that the Stereomour will make you a good deal happier. I played both the SEX amp and the Paramounts on my Chorus and, while I wouldn't hesitate to recommend the SEX amp if that is what you can afford, I preferred the Paramounts. The Steromour isn't a Paramount of course, but if you can put in a few more dollars I think the Stereomour is going to provide better sound through those speakers and would be my choice.
But some other factors, it sounds like you are going to be using multiple sources. You need a preamp like the Foreplay III for switching sources easily. If you are going to be doing reel to reel you need a Seduction for reel to reel, correct? If you are going to be using a turntable you need a Seduction for your phono preamp. So you need not only a worthy amplifier but also a preamplifier and at least one phono preamp and maybe one for reel to reel.
Let's not even get started on upgrading the crossover. It makes a difference ut isn't something I would worry about right now.