u sir are the man and got a pmu can do 40wide x 20high x 30deep and get it in there with no problemif u use 1 inch wood u can do it 2 18's subs up port up
80
I have 2 18's under the window line in a car smaller than your, but i sacraficed the back seat
almost the exact dimensions of my box with 4 6" aeros..Sundown 18's would be happy in there. 40x30x20 is 11 cubes gross before sub and port displacement. That's not a lot of space, round areo ports will help.
Is it a red magnum with a fosgate 3000 on 24'sdo it dude i seen a guy running 4 t2's 15's in a magnum i would love to see what yours sounds like