Harbeth 7es2 vs Harbeth 7es3

Personally I would pass on a speaker that has been modified, especially by third parties. Similarly like Chashas1, I would pick an original C7ES2 over a modified speaker. You wouldn't know the quality of workmanship of the modified speaker and the true performance of the originally designed speaker.

Good luck.

I own a pair of C7ES2 and have the upgrade itch. It may just be cabin fever. I was wondering what I would gain by upgrading to the C7ES3.

a much tighter, seemingly lower bass, for one.
also an increase in clarity.
definitely noticeable.

I've heard both. I favor the 7-ES2. Even though they are older, I feel the sound is more accurate, with zero listening fatigue and midrange to die for. The 7-ES3 is great too, but perhaps is adding some coloration in the lower frequencies. Both generations are examples of how fine, monitor-style loudspeakers should be engineered. If you have superior recordings in your collection of music, you will want to listen all day long.

Having lived with both speakers, the C7es3 is clearly an improvement over the C7es2. However, that said, if i already own a C7es2, i would leave it as it.
Both speakers are great & either one is very very satisfactory.