need help on my box

[mizael]

Hi guys I need help with my box I have an Fi btl N2 18'' power by a sundown Saz 4500 electrical is upgraded. my goal is to hit a 150 db and recently I did a 149.5 db the box was tuned to 33,port area is 96 in, 16 inches of port per foot, and is 6.25 cubs after port and sub displacement. right before I hit that score over excursion took over and broke the sub so now I need help designing a new one. people have tolled me I need more back pressure and less port area 4 cubs and 70 to 80 in port area what do you guys think ? Also my car is a mini SUV sub is facing up and port is firing back.