sub-woofer with ML Summits

I just bought a pair of ML Summits, and although I am still breaking them in, I adore them. I am brand new to this level of hi fi listening and not very knowledgable, but already I'm hooked. I had owned the ML Ascent i's and a ML Descent and loved them too before trading them in for the Summits about three weeks later. I figured I wouldn't need the subwoofer, and indeed I don't, but there's need and then there's need. I listen to mostly classical and jazz, often at quite low levels, and I'm wondering whether a subwoofer would flesh things out even better down below despite the Summits' marvelous tight bass. My listening room is about 15 ft. x 26ft. If the answer is yes, any suggestions which subwoofer? A Depth? Audio Physic? I'm in France so it's easier and cheaper to buy euro brands?