Besides the obvious power differences, is the sound any better at moderate + levels from the larger Onkyo M-508 and M-5090 vs the smaller M-504 and M-506rs (And the M-5030 and M-5060)? I love my Onkyo A10 and want to try an amp/preamp, and am having a difficult time finding a M5090 or M508. The rooms I listen in are about 15x20, and I'm currently using JBL 4412's or Poneer CS-R700's. On the same note, is there anything to gain by using the higher numbered preamps? Thanks
