im running a set of 4ohm speakers rated at 200wpc and an efficiency of 92db. im using a 150wpc @ 4ohm amp and it seems to struggle to get the room to pressure, and the bass extension is not enough to satisfy me. the dynamics are ok at low volumes but quickly decline with gain. my room is 12.5ftx25ft. all watts are not created equal. i suppose that contradicts myself a bit, but it also proves a point.