I'm surprised no one has actually asked you any questions about the vehicle.
Do you have the bench seat or captains chairs?
Also, how tall are you? This will allow me to see how much space you are willing to give up.
If you are 6'4", I would say...yea....you are horribly limited. But, if you are 5'6", you have some 'notches' to give up on seat position to allow for the enclosure.
For aesthetics sake, I would recommend staying behind the seat w/ the system rather than building a center console.
If you can give up the space behind the seat, you have enough to allow for 4-8's ported. This would provide a very solid lownote and loud system.
Though some may recommend shallow mount subs, I have found that most have a hollow sound. (I have not heard the MB-quart or BM though) I will say that a SOLIDLY HATE the sound the shallow Memphis sub produces. I have only heard it in 3 installs, but IMHO, it sounds like every other shallow/flat sub I have heard. Weak, hollow, and pingy. These designs seem to regularly sacrifice function for form.
If you can allow for even a pair of well designed 8's in a properly designed ported enclosure, I will guarantee you will be much more pleased with a properly designed 2-8" enclosure....so far as sound quality is considered.
If you can manage as little as 2.5cuft net behind your seat and the mounting depth to allow for a solid 8", you can have a nice 2-8" enclosure.
If you are short (like me...lol) and can allow for ~4.3cuft, you could have a SICK 4-8" system!!!