I tried to find an impedance curve for the Cerwin Vegas but came up empty. My concern is that the impedance may dip down to 2 ohms in the lower frequencies. The Pioneer may be ok at lower volumes but if the op is into rock and metal he's likely going to want to crank up the volume at some point and I wonder whether the Pioneer is up to the task. Will help to know what other gear he has and hopefully we'll get a more detailed list.