Bandpass for 12W6V2 D4 in the Audi TT convertible

Hi together! I’ve been driving a TT Roadster 8N for a short time. Only way to get what bass in here would probably be a band pass that pushes through the really small ski bag opening (if you like to call it that). Music is all there, from Kindertechno (Cascada) to Bullet for my Valentine, now and then also Eminem. Can one please make me a housing proposal or calculate that? I need another new HU, and a reasonable FS. Box I therefore wanted to build UNBEDINGT myself, because otherwise my financial framework will be blown up. Just for the general info: As final stage is available ne Boston GT 28, so power is enough for the W6..