Okay, I'm getting ready to order a XPA-5 amp from Emotiva, and I was also seriously considering getting one of the ERM 6.3 monitors as a center channel speaker as an upgrade over my current CSi30. My mains are 8 ohms and the center will be 4 ohm. Sensitivity is 89 dB for both speakers (mains and ERM 6.3). Will there be a problem running 8 ohm mains with a 4 ohm center (being driven with the XPA-5 in three channel mode at 250 wpc)? My guess is it should not be an issue since the sensitivity is the same...