I'm thinking of getting 7.1 speakers. The front LCR will be 4ohm, while the 4 surrounds will be 8ohm. All 7 have power handling of 100 watts. BTW, the LCR are Gallo Due's and the surrounds are Gallo Micro's. I've heard that many mid-range receivers have trouble driving 4ohm speakers. Is this true? Regardless, is there an issue mixing speakers with different impedances? I emailed Gallo asking if this would be a problem and they replied with the following: "No, although you will have to give the rears a little more volume level" Thanks.