AB1 or REL Subwoofer for Ls3/5a?

A friend of mine is going to hook up the Rogers ls3/5a (11Ohm version) with the Quad 34/405II combo. I need to suggest to him a suitable subwoofer. I narrowed down the choice to two one being the obvious choice of an AB1 subwoofer and the other being the REL (probably the Q series).

The reason I picked up the other option of REL was due to the fact that another friend of mine has set it up with the Alon Adrianna's and Cary 2A3 5 watt triodes. They sound amazing with the REL introduced into the chain. Alon by themselves are excellent monitors but REL Stantor added to the spectrum what we thought was not required or to put it precicely did not know was missing.

We do not have the luxury of auditioning either of them with the system so I need to do some homework before we finally decide which one to go for. Any information given to help decide which one to go for would be greatly appreciated.
Re: audioning a subwoofer before committing. I suggest
you try an ACI Force or Titan II LE -(www.audioc.com).
ACI offers a money back trial period. I didn't need to
return mine. The Force integrated seemlessly with my
Thanks for the tip will check it out. Meanwhile will also wait for anyone else having any opinion on Rel subwoofer paired with LS3/5a's.

Thanks again, appreciate your input.
I have tried REL strata 3 with Spendor S3/5 and it worked very well. A friend runs with spendor's own subwoofer (perhaps another consideration). The REL was set to cross at 70Hz, and it was pretty seamless.

The only downside to the AB1 is that I'm not sure how transferrable the sub would be if you were to change the monitors, whereas the REL will blend with almost any speaker out there.