I ran into the same situation and I'm looking into adding the DSP. I checked with Louie at Pacific BMW's mail order dept. He didn't have much of the details into installing it but he did say that the DSP can be ordered for $689.00 (retails for $995) You can have this plugged in to your audio system but the dealer has to code it. I didn't get the info on the amp and the subs. Maybe someone on the board can comment on this.