I am sure it can be done better, but I thought that Burmester in SL Coupe does sound really good. For some reason, and it might have been my bad day, it was a notch less good in the sedan. I never fully understood the idea of moving tweeter that was in some promo material, but it might have been just a marketing gimmick and not anything particularly useful.
My mention of Cadillac Escalade was after reading all those posts about bass. They reminded me of usual experience with Escalades next to me at the red light. My car shakes from their bass. That is how I imagine 4, 5, or 6 subwoofers would be in the room. Nothing wrong with that, if someone likes it. I went to check what Escalade offers because I would be surprised they did not notice what their buyers frequently like.