A Stereo amp for the Marantz 7011

[Barry]

       I have a question:
 
My brother has a Marantz 7011 running a pair of SVS floor speakers and smaller SVS speakers for surround. He has the Ultra for the center.
 
While the Movie Surround is just great, he feels that the sound could be better for his SACD/CD playback.  He wants to get a two-channel amp, with more power, to get better sound. 
 
Have anyone done this? What amp would you recommend?
 
He also thought of stepping up to the 8015 but thinks that a powerful amp would probably be better.