it's not as simple as buiding the biggest box tuned really high and lots of power. it depends on the vehicle itself. it's fr (fs?), the install, how well the box is built, how efficient the subs AND amps are, how clean the signal from the HU is, your power wires, electrical system, etc etc. and lots of sound deadening/dampening.
if it was that easy, someone would've already figured it out by now.
what works for one vehicle may not work for another. i bet you could have the same exact vehicle, with the same exact setup, everything the same done, and still have different results.
it's just not that simple in SPL.