I might can offer a little insight. I might not be the best at making a BTL sound great in a box, But I got my 12" pretty darn loud for no testing what so ever.
Everything closed, 12 inches from the pillar 4" from the bottom of the windshield, car on so I dont kill the battery. Sub forward, port back 1.695 net with 2 4" aeros at 17" long. I havent shortened them any, but I was burping in the low 50s.