4 Flat Subs Vs. 1 Conventional Ported

[Ben Building]

I have a 2002 Ram Quad Cab that's in dire need of bass. I'm spoiled by deep, loud bass but don't want to compete with this truck. The only space available (no wall or blow through this time ) is under the rear bench seat. There's a big tub about 10 inches at its deepest. Let's call it 2.5 c.f. Should I use that space for three or four flat subs in a sealed 'glass box or would I get more output from one high-power sub in a ported box?

I don't have much experience with flat subs, so I'd really like to hear from you guys before I waste a bunch of time and materials on a box that doesn't sound like I want it to.

[Boon]

IMO one high-powered sub ported. Those flat subs tend to be pretty... average.