the rl-s is an amazing sub. the sq is best i've heard. i used to have the jl w6, treo ssi, alpine type x and the re se xxx. the rl-s destroys them all.
the amazing thing about this sub is how low it hits and maintains its sq and control at those low bass notes. also in a sealed box, the frequency response is very flat. not one note is louder than the other.
only downside is the upper bass frequencies. it lacks a bit above 70hz. but if you have nice comps up front, it won't matter.