I had a 6.3, and agree: no tubes! The amp will sound pretty fat. Tried AES Sixpacs with little luck. I ran my McCormack DNA-125 and it sounded very full, but still detailed. Probably either a lean tube sound, or a good SS amp is best. And, they need a bit of current to keep control of the woofers. I actually had great sound with a C-J MF2200 amp as well.
If looking at integrateds (your budget wasn't stated) then perhaps a fairly high current model like the Karan will bring out great things, or Simaudio I-7 perhaps.
If looking at integrateds (your budget wasn't stated) then perhaps a fairly high current model like the Karan will bring out great things, or Simaudio I-7 perhaps.