Help! I'm upgrading my front and center speakers. Currently have Denon AVR-2802 receiver and Sonance 622T (8 ohm) rears. I've purchased Polk LC65i in-walls for front and Polk LSiC for center. However, I've now looked at Polk's website and see these are 4 ohm speakers. My receiver's specs don't mention 4 ohm load. The Denon's rated output specs are: 90 W, 8 ohm, 20Hz - 20kHz with 0.05% THD 135 W 6 ohm, 1 kHz with 0.7% THD Should I avoid using the Polk 4 ohm speakers with my receiver? Does it matter that my front/centers would be 4 ohms, while my rears are 8ohms? Thanks!