Smdavis,
You don't need a new receiver, just add a quality high current outboard amp if you feel your Marantz doesn't have the gusto to do a proper job of powering your B&W's.
I recently owned one of these Parasounds and it was a fine amp that seemed much more powerful than it's rated 125w/ch output.
http://app.audiogon.com/listings/solid-state-parasound-2125-7-units-available-2012-09-19-amplifiers-75165-waxahachie-tx
Bill
You don't need a new receiver, just add a quality high current outboard amp if you feel your Marantz doesn't have the gusto to do a proper job of powering your B&W's.
I recently owned one of these Parasounds and it was a fine amp that seemed much more powerful than it's rated 125w/ch output.
http://app.audiogon.com/listings/solid-state-parasound-2125-7-units-available-2012-09-19-amplifiers-75165-waxahachie-tx
Bill