Ok, this is slot port, probably the only way it'll work. 18H X 43W X 15D will yield, before displacement, a tuning of 32.41 (will go up after sub is in) if it is 15"W X 3"H X 17" long. It would be an L shapped port, so you would have to bend it after the first 15" and make a 2" extension perpendicular.