FAUguy,

Isn't 40 Hz a little low to run the crossover for the fronts? The B&W's have their +- 3 db level at 44 Khz, so you're creating a fairly large bass dip between 40 and 50 Hz or so that the sub could easily cover. It would also take off a lot of strain on the 603's to set the crossover at 60 or even 80 Hz.