No clue about JL subs but I do know that REL knows how to make subs...I rant about my decade plus old Q150e as it works extremely well, and I'm on board with the "high level" input technology as it renders the signal cable length issue irrelevant. A friend who has the same main speakers as I do uses a newer little 8" REL and it sounds great in his system. Use common sense setting up any sub and simply watch the levels and you can obtain a beautifully balanced sound...I turn my REL up and down depending on the source bass level and how loud my listening level might be...louder if I'm drinking heavily and dancing with prostitutes, softer if I'm trying to locate grouped violas...never lose track of grouped violas...trust me.