well if it is ported then it already has a tune. depending on the size of the port determines the tune of your enclosure. If you tune to high say 50htz then you are at a serious risk of damaging your subs do to overexcursio at levels below tuning. The sub loses its ability to be controled properly under tuning. The higher the tune the higher the SPL the lower the tune the better the SQ. Higher tunes are for competitors mostly but they only burp their systems for maximum output at a controlled htz above their tuning of their enclosure.