1 12 sub vs. 2 8 subs

 I have a 2004 F250 with very limited space for subs.  My options are either a single 12" or dual 8". I need your opinions. Thanks.

yeah, what kind of subs. some 8s are still very deep, like JL w7's sealed box i presume? how much watts you thinking about running?99 Blazer LT.   Yellow Top. Big 3. Infinity Kappa Speakers All Around. Jensen CD/DVD flip out. 2 Infinity Kappa Perfect 12DVQs powered by a Alpine PDX600.1 (in one custom box, building a FG box)

We've built a two 10 box for some Polk Momos (don't need much air space) in a couple of those to fit behind the seat.  1/2 inch mdf was used to save space, the back of the box was slightly notched for the magnets to clear, and we double-faced it to recess the subs.  You'll have to remove the vents behind the seats, too.  They all turned out nice.  You can remove the luggage rack from under the back seat and mount your amp there.My ex once told me I have a perfect face for radio.

I Also have a space problem in my ford sport trac, I was limited to using 8's but I found some infinity reference 8" subs that are designed to perform in a limited amount of space. I just custom made two sealed boxes to fit under my rear seats. Nice. I have always preferred the sound of dual subs rather than a single, dont know if its any different but to me it sounds fuller with duals.what?,I cant hear you

Can't help you make a technical decision, but because of boot shape, space etc. I run 4 8'S in a sealed box in my sedan. It ain't the deepest sub by any measure, but its smooth as a gravy sandwich and has heaps of control. I prefer drivers over inches (please dont read that last phrase incorrectly, its clean!)