I actually had a JL 15W6 and switched to a 15 Rl-p. I used the same box, 2.75cft, tuned to 30hz, and it is a big improvement in spl and sq. I love the 15w6, but the rl-p gets much louder and retains great sq at higher volumes.
Also, while both get loud off of little power, the rl-p can take...