Rel B3 or JL Audio F110

Another vote for the Rel (I have the B3) and want to add by replacing the stock Rel cable made the sub a world more musical. Much better attack and decay. I have a Nordost baseline made to Rel spec (there was a $35 up charge for the speakon connector).

Forgot to mention. Getting the timing/phasing right is the tricky part. I would assume the JL would be the same. On the Rel there is a phase switch 0 or 180 degrees. Then you have to physically move the sub closer or farther to get it right on. Once you get that right the crossover point and gain is pretty easy. You should not be able to hear where the sub bass is coming from.

Good Luck