Considering the Klipsch RC-7 are rated at 98dB sensitivity, even if that is an over-optimistic rating they are still relatively high sensitivity speakers and should be happy with your 100W/ch @ 8 ohm amplifier.
The Emotiva XPA-5 has a slightly larger transformer (1,200VA vs. 1000VA) but only half of the storage capacitance (60,00uF total vs. 120,000 uF total), so the Harman Kardon actually has a stronger power supply relative to it's lower (half) rated output.
Specs aren't everything of course, but considering that the HK Signature 2.1 was considered by many to be a very good sounding USA-built amplifier along with the relative high sensitivity of the Klipsch speakers, I would say to stay the course and enjoy. If you change to some low sensitivity 85dB speakers in the future, then depending on your listening habits the conversation might have to be revisited.
Steve