Adding a Rotel RMB-1075

I have a Rotel RSX-1057 5.1 Surround Sound A-V Receiver used primarily for music and less for HT. I now have a Marantz SACD player and am absolutely loving this new format in multi-channel 5.1. Fabulous. Am building my collection of SACDs now. The RSX-1057 is conservatively rated at 75 watts/ch x 5 in to 8 ohms at 20hz-20khz all channels driven. My two main speakes are the B&W DM603-S3 with the full complement of B&W center channel, surrounds, and two powered sub-woofers. Sound is out of this world. I'm thinking of my next upgrade and am considering adding the Rotel RMB-1075 multi-channel 5.1 amp at 120 watts/ch in to 8 ohms all channels driven and use the RSX-1057 just as a surround sound processor. What would I get out of this addition? Would I get more out of my mains and center channel because they're now being driven by more raw power? Would I realize more of the potential out of my B&W speakers? WOuld I really hear a considerable difference going from 75 watts/ch to 120? More slam and punch, more detail, more information, greater soundstage? Thanks all.