Mine was also in a much smaller space.I dont find it "OMFG I cant Believe it".......its achievable....come on Tommy...you were doing 154s with urs and 2500watts....whys this more difficult to believe than that or your 10 doin 150....regardless if you or him proved it or not on video
it was not suppost to be spl but it worked out to be. its the smallest box i have used for the 15. its 2.66 cubes. you have more experience than me with these subs though.Mine was also in a much smaller space.
An SUV with that much air to pressurize isn't going to get as loud as easily, IMO.
It certainly is possible given the right circumstances, but I don't think THAT particular setup is capable of it.
But I've been proven wrong before.