I thought you ment it was a 2 ohm final load D4, not a d2, sorry. I'd use the first amp you mentioned and run it wired in series for 4 ohms and 500 watts (I believe that's what you said it did). I don't know what those type R's will handel I know they're rated at 300-350, but I've heard they'll take more.
But anyway, wired in series to a 4 ohm load on the first amp for 500 or less watts is what I'd do.