Unfortunately, they're the only thing I've got. I've asked Klipsch directly, but they're tight lipped on the subject.
It still matters in terms of amperage, which I also calc out. 5 channels worth of speakers dipping down to 4 ohms or less has the potential to demand a fair bit, even with the relatively high voltage sensitivity they present. But again, I'm not doing this because I expect huge audible differences; it's peace of mind in knowing that I can push things to 0dB and expect clean unclipped output pretty much regardless of how full of it Klipsch is in rating their speakers. Of course, I never actually push things to reference making it completely arbitrary, but that's beside the point
Reference level is typically an 85dB average level, but each channel can peak up to 105dB, and they can all potentially peak simultaneously (though they rarely if ever do). I calc to the 105dB level; just for an example, into a 4 ohm load, with 95dB @ 2.83V, you're talking about ~135W into a 4 ohm load for one channel, which is a little under six amperes. Multiply that times five, and a midrange receiver could find itself in a world of hurt. Might not be real world, but I prefer safe over sorry. Plus lets face it, whatever I end up with is going to look badass, and that's half the fun too