The NAD 355BEE should be a notch up from the Azur 340A.
If you really want to get a little more grip on those speakers, don't have a problem with a separate preamp and power amp, and don't mind buying used (preamp new in box/power amp 2 yr old), you could get a
lot more bang for your budget buck with something like this, both currently available right now on Audiogon:
Parasound Model 2100 Preamp - New in box for $425
http://www.audiogon.com/cgi-bin/cls.pl?preatran&1260458157&/Parasound-Model-2100-Pre-with-
and
Parasound New Classic 2125 Power Amplifier (125W/channel) - 2 yr old, 9/10 condition for $375
http://www.audiogon.com/cgi-bin/cls.pl?ampstran&1262200344&/Parasound-2125-New-Classic 
I think that would be a very nice, powerful, good sounding and fairly sexy new/nearly new setup for $800.
I have owned an older B&W 600 series, and found the metal tweeter just a little bright and the bass just a bit boomy. If you found either of these true with yours, you might consider trying the foam port plug and/or moving the speakers out a little farther in the room, and may want to try Jim Goulding's Touchstone Tweeter Surrounds.
http://www.diffractionbegone.com/newblankcontact.html Steve
Note: The seller of the preamp, Ericus Rex, is an Audio Circle member. I don't know the seller of the power amp, but he does have 2 positive transactions