My personal experience was similar to yours; trying to improve on the sound of Vandersteen 1Cs. I had a Def Tech sub, but it wasn’t doing the trick. I eventually acquired a pair of Vandy 2Wq subs. Better, but I still found the sound wanting. I upgraded from the in-line crossovers to the M5-HP battery biased crossovers and heard more transparency, but still found the system wanting. Too much etch and grain and congestion in the upper-mids and lower trebles. After upgrading my amp, preamp, DAC, cabling and power filtering, and treating the room, I finally concluded I had taken the 1Cs as far as they could go, without satisfactory results. But those 2Wqs I absolutely love, and still have. In fact, when I began the search for new mains, one requirement I had was that they reach 40Hz without any issues so that I could keep the 2Wqs in the system (they are that good, IMHO). In late 2009, I tried a home demo of Ohm Walsh 2000s, and have been thrilled with them ever since. I have heard many, many systems, with and without subs, and I would never go back to a system without subwoofers. Just my 2 cents; YMMV.