Best Integrated Amp for B&W 602 s2 +/-$500 used

Fresh on the heels of a successful query regarding speakers for my Creek 4330r (went with the obvious - a clean pair of Epos ES11's) I return seeking advice on what to power my now-idle B&W dm-602 s2's. They have previously been connected to the aforementioned 4330r (40 watts x 2) as well as a new Onkyo TX-8050 (85 watts x 2) networking 2-channel receiver. The problem with each hook-up is that the overall sound was rather congested in the mid's and loosey-goosey-boomy in the lower regions with sometimes lovely highs but not what I'd call open or airy. I like, or rather want to like, the 602's so I'm looking for what integrated amp would make these things sing ($500 +/-). I'll use them for itunes streaming (via Airport Express) and the occasional TV & movies (moving the Creek/Epos into the fun room for vinyl, etc). Using Canare 4s6 Star Quad speaker cable and Chord Cobra 3 ic's with the 602's perched atop quality, mass-filed stands. Any thoughts? Thanks,
Jerry