Theoretical random audio question

[out4u]

So this is kind of random but i was just thinking about random theoretical stuff i haven't seen lol.... so what would happen if you had like an suv with subs behind your back seats (or wall behind them) and built like a port in the window attached to the inside so when u roll it down it has more length to it being that most systems get deeper and louder with windows down or door open. Not like i have any plans of doing this or anything just kind of curious what the knowledgable audio gurus have to say