anyone have any experince doing SPL burps with the 4th gen maxima? my 52hz port didnt do shizit..

I peaked some where around 38-45hz so the 52hz port was useless i should had left the 40hz port in the box but i did do a 146.6 on the TL

also i heard i have to tune the box 4-6hz lower than the cars req. freq. correct? Then from there i should be good right? and from the look of the testing i should be musical too..

Lastly i ran out of test tones at 55hz is it possible for the maxima to spike again later? like around 54-68hz or something like that?