Which rels do I go for?

Which ones do I get if I am looking for a subwoofer that adds just a light touch to my already accurate sustem. I have a small room and my merlins do have bass. Could I get away with the stampede's or do I go for the strata or even the storm and set them on low volume? I want accuracy and imaging more than anything else.
You mentioned on an earlier thread that you are running Merlin VSM Gen IIIs. Not quite the exact match but the following review mates a REL Strata III with the VSM SEs:
(Apologies if you've already seen this.) The reviewer comments that it might be better to get two Strata IIIs instead of one Stadium II. One caveat, the review was apparently written before REL introduced the B and R lines, so it doesn't actually tell us if the reviewer would have thought that a B or R subwoofer might have been a better match with Merlin VSMs.