I am his buddy with the 2000 328i BMW, it is also a sedan and I literally just punched out the sheet metal in the middle, I also didn't want to lower the integrity of the beamer, so I also took out just the foam in the middle and left all the rest of the foam that was behind the seat, and when I the armrest is down, it allows my sa-12 powered by the 2010 model brutus (BRZ2100.1D) and it takes all 2100 watts and loves it, to allow air into the cabin. But when I fold the center armrest up, it becomes just as quiet as before... it took alot if thinking and how I wanted to do it before I actually committed to doing it. I am very pleased and because of where my amplifier is mountd, I get the awesome hifonics blue light in car, subtle but nice if you ask me or anyone who has seen it