am confident that I am not alone in thinking that there are instances where the CS 2.7 and/or the CS 3.7 would require subwoofers.
Utilizing a proper power amp will not unto itself act as an equalizer to yield aural results across the frequency spectrum beyond the scope of a loudspeakers limitations.
That's a timely comment for me, as I just spent the last couple days
checking out my new CJ amplifiers. I've used the CJ Premier 12s for 20 years and just grabbed a pair of Premier 12s that had been upgraded with lots of the CJ "Art" series upgrades, Teflon caps, works better with KT120 tubes etc.
Wow, it's literally sounds like my speakers got bigger! The bass depth and soundstage are just huge, and seem to give up little to nothing to what I remember from my Thiel 3.7s. And it sounds better to me than with the subwoofers I had (which I just sold).
In no way would I dissuade anyone from adding subwoofers to their speakers, Thiel or otherwise, as there are plenty of happy listeners who have done so. But having had the 3.7s, and the 2.7s with subs, I'd take the sound I'm getting now any day.