That is totally unacceptable. You adjust the wakeplate all day, all the way down when getting out of the hole, and then for the riders preference. I would report the dealer to SC for being stupid. I am amazed that you spend 35-45K on an item and they give you that type of solution......

Sounds like a power or grounding issue. So when you unplug the stereo from the power amp (just drive the onboard speakers with the stereo) you do not have any popping?

Pete