typically, a box tuned to just below the sympathetic frequency of the cabin would be the loudest, though it would sound a bit boomy since tuning frequency would be around 50Hz. Tuning just above the Fs of the driver is done more for low bass and musicality as opposed to SPL. tune low for SQ. tune higher for SPL.
for positioning it varies. try downfiring. That often works out very well.
hey i need some help.. i'm tryin to set up a hard hittin system i want the best in my town but idk what to get between type-x.. audiobahn immortal... L7s... kicker comp VX... W6v2s...thunder 9500s.. or fosgate T2s..them i need to know what amp i would need for 2 12s of w/e i get... keep in mind i'm throwin it in a 93 talon