soundstream ref4.920

I'm wanting to buy a soundstream 2 channel that will match my reference 400.4 I have already. A reference 200 , reference 2.370, or something belong those lines will work. Must be in working and mint condition. Thanks. Here is a photo of what my ref 400.4 looks like, it must be close to...

I need some details on both of these amps, they are made by the same manufacturer I believe. The REF seems like it would be better on SQ and has a much better crossover. The P900.4 on the other hand is class D so it's much more efficient, but doesn't have a great crossover so I don't think I'll...