I have not heard the 2.7's but I own the 3. 7's. IMHO, the only sub to consider with the Thiels is a Thiel smart sub. They are built to match your speaker.
There's simply *no* way to know, without experimentation in your room, whether a sub would be better or would even work well in your room. I've heard them make a great difference and frankly not much at all. Can you get a dealer to let you audition one?
One thing to consider is that the 3.7 will be phased out soon. The new company is going in a different direction. The new speakers are not time coherent. I predict used 3.7's will hold their current value for some time because they punch way above their weight class and have a relatively small footprint.FWIW.
There's simply *no* way to know, without experimentation in your room, whether a sub would be better or would even work well in your room. I've heard them make a great difference and frankly not much at all. Can you get a dealer to let you audition one?
One thing to consider is that the 3.7 will be phased out soon. The new company is going in a different direction. The new speakers are not time coherent. I predict used 3.7's will hold their current value for some time because they punch way above their weight class and have a relatively small footprint.FWIW.