How much room would I need.

[miker 5,000+ posts]

You need to take into consideration the thickness of the walls and inside baffle. You could cut the airspace down slightly but that would detract from the benefits of the bandpass. Unless you have the dimensions to go bigger then a simple ported box would be a better choice than a compromised 6th order bandpass.

Oh, alright..

Ugh, I just need a new car.. lol. Can't fit shit into my trunk.