cheap Yamamha amps on ebay-any good?

I ve been considering a Yamamha integrated and noticed some heavily discounted models( new) on ebay. I presume these are " grey market"- whatever that means. Does anyone know if there is a problem with these amps such as wrong voltage for US, or anything else?
Grey market means goods sold without the factory warranties aka outside the dealer network.  Doesn't necessarily mean that the items are damaged.  
What model #'s were you referring to?

If you like real garbage buy it on ebay good luck getting a winner.