Assuming the Maxx 11 really need a sub I would look at the REL Studio and use it in parallel with the Maxx woofer and set to the lowest possible crossover frequency. But are you sure that you really need one, what is the Maxx 11s bottom end cut off? The smaller Wilson's I have heard do not seem bass deficient.
Subwoofer to go with Wilson Maxx II's
I'm in the market for a Sub to compliment my Maxx II's. I thought I wanted a powered Watchdog-and still may. I read a review that said it may be-choke-inadequate. Never thought I'd hear anything written about Wilson's with that word in the same sentence. In it's defense, reviewer was referring to below 20hz sound in home theater. I like movies, but my main emphasis is music. Any recommendations or comments about the Watchdog?