[Msquared]

2019 was the first year of the new communications protocol in all Camaros, going from MOST to ethernet. We know that the factory radio modules changed, and I assume that means the Bose amp had to change as well. Since all the DSP for the system is in the amp, too, Bose would have had a chance to redo its calibrations. Maybe the amp's internal hardware is actually different, too. I'm not sure. I assume the drivers all stayed the same, though.

I have no idea about measurement differences between the early and later 2SS systems. Keep in mind that "louder" could mean that it's legitimately pumping out more decibels. It might also mean it's giving you the same sound pressure level but other things are different that make you perceive it to be louder.