Thoroughly confused here. Looking for amps to push (2) Diamond 12' and Diamond 6 1/2 component in a A6 2001 2.7T. Looking at Phoenix ZX475 and 600, Orion XTR Series, Xtant and Soundstream Rubicon series. The diamond subs need alot of power. Any thoughts??

When dealing with high end amps, the differences will be imperceptible to your ears. Instead of worrying about brand names, concern yourself with buying the most high quality watts for your dollar. Don't forget all the other great amps out there, such as U.S.Amps, Zapco, PPI, Pioneer Premier, Alpine, Sony ES and so on. Buy watts, desired features, and service, not a name!

Assuming you purchased the Diamonds for their clean, smooth sound I would recommend the a/d/s amp. If you bought the Diamond 346is or 236is series (one midrange, one tweeter) then you could get the a/d/s/ p650 or last year's 640.2 and bridge for the two subwoofers. They're not the loudest amps but they are amongst the cleanest you will ever hear.