I'm a competitor in MECA at my state finals I managed to reach 154.4 at the headrest using two 15 in btls and using 2 American bass 500.1s. I can only give high praises to the newer style BTLs It took a little tweeking to get them there but with any new setup it takes work to get it loud. After about 75 burps I have on the subs with about 7500 watts to the pair these subs are still like new no signs of wear