Just FYI, there were two different birthsheets for these amps. One was a smaller one (about a half-sheet of paper) that showed 600-something W. The other one was the full page one that showed actual power output to be 800+ W.
Some of the amps were shipped with the "real" birthsheet, but a lot of them didn't.
Good luck finding an onyx one. If you'd settle for the silver, I've got one FS right now. Sorry, if it had come with the "real" birthsheet, I would have it.