I'd also note that my mains are B&W N804s with and HTM2 center, which are not exactly power hogs, but not all that efficient either. I used to power them with a separate Rotel Amp until it died because I thought I had to. Now I am using the 4311's internal amps as a "backup" except now I don't think I am going to replace the amp. They just sing with the 4311, although I have them crossed over at 90 Hz with a Submersive HP pulling the heavy loads down low. With 9 channels of assignable amps, there are a ton of things you can do with an existing separate amp, and, again, its always nice to have a nice backup amp if your external amp goes tits up.