Re: custom sealed enclosure
First step is to pick your woofer. This way you know how big of an enclosure to make. I assume down firing would be best in this application, since passengers will likely be all over the sides/top of the console.
Post up some dimensions too and go from there.
2003 Volkswagen Jetta GLI VR6
Source: Pioneer 880 PRS *Active
Tweeters: Soon to be Hat Imagine
Midrange: Soon to be Hat Imagine
Sub: 15" SSA Icon
Box: 2.5^3 Sealed
Amp: Soundstream Tarantula 2kW