I just got off the phone with SSL and once again it was clear that they didn't know what they were talking about. After teaching the rep what an unregulated power supply was, he told me that the amp was regulated but that the output voltage would drop based on the input voltage (so unregulated). He also said that he doesn't know what rating methodology is used but it definitely isn't CEA.

Since I was able to get full power out of it (with the car on) I know the amp is capable of 50W. My issue is that it takes maximum gain to get that power. Could this be a ground issue?

If it helps, I measured voltage across the power and ground terminals at 31.2V. I'm not sure what the significance of that is.

Also, according to the DMM, the speakers cannot handle 50W (Though they're rated at 60). While playing a 1khz 0db tone, the sound changes from a clean tone to a gnat-in-your-ear type sound at 7W (5.5V). But according to my ears the speakers sound like they're getting much more than 7W. What's going on?