Good Sub for Martin Logan ReQuests, Help

I have some ML ReQuests and they are in need of some bass. Thinking of the Rel Storm III or the Genesis 928. Which is better for the ML's. Rest of my system is BAT VK5i/Bryston 4bst. Any advise and comments are very much appreciated.
I asked a very similar question here last month when I was looking for a pair of subs to augment my ReQuests. Audiogoners referred me to a number of excellent subs which may also be suitable for your system. See replies to the post "Talon Roc - worth it?" at . After spending some time auditioning, I ended up buying a pair of Talon Rocs. Their speed and detail are a very good match for the lively electrostatics. My listening room is not very big and I've now found one Roc is plenty for my system (even for HT) crossed-over low with -3dB bass setting on ReQuests. A new powered Roc lists for $4000, but you can probably pick up a good used/demo unit for $2000-$2500 (depending on age & condition). The Roc is well built and comes with a transferable warranty. The Rel Storm is also very good (maybe a tad slower), though I didn't get to hear it with MLs. I didn't get a chance to audition the Genesis model you asked about, so can't comment on how it compares. Hope this helps. By the way, there is some other info you may find useful in the thread just below entitled "1 sub? 2 subs?" Don
I have a pair of Quest Zs which I wanted to run without a sub but there just wasn't enough deep bass. I tried a B&W, I had a Mirage in for awhile & sold that. I went to a REL Stadium II & after spending some time dialing it in I am very happy with the sound I am getting.
My Bag End Infrasub 18 worked great with my ML ReQuests.

broken-record-time again... ;~) get TWO subs for audio... works best imho...
Try a preamp upgrade. VK5se or 50se will have more bass than the 5i. Otherwise, look at the Titan II from