All my M&Ks are 4 ohm speakers and my ATI 2005 (clone of the Outlaw 7500) runs them just fine. Last night was good example: I watched a couple of movies at pretty high volumes and my amp didn't even get warm. Speaker impedance varies depending upon the frequency and every curve I've seen shows the vast majority of the time speakers operate above (sometimes well above) their impedance rating. I suggest you pick the speakers that sound the best to you and forget about the 7700. It will be fine driving just about every commercially available speaker.