Harbeth 7es2 vs Harbeth 7es3

A good place to look would be the Harbeth Usergroup on Harbeth's website. Alan Shaw, the owner participates in the forums. That question has undoubtedly been answered there already

In the Harbeth User's Group, regarding the new C7ES3 vs the C7ES2, Alan Shaw states:

"I think the differences between the C7ES2 and C7ES3 have been documented here or on the main Harbeth web site ....

They are:

C7ES3 has ....

1. A new woofer
2. A new tweeter
3. A new crossover
4. Revisions to the cabinet damping arrangement that would be difficult to retro-fit to ES2 cabinets
5. Longer ports
6. Single wire, not bi-wire terminals

A Compact 7ES3 is the sum of all these parts and any lesser combination is not, technically a Compact 7ES3. At this time, and especially because of item 4 above, there is no upgrade path and we do not want to have a half-way situation between C7ES2 and 3 whereby 1, 2, 3, and 5 are upgraded but not item 4 (the cabinet)."

Based on the above, the C7ES2 and C7ES3 woofers are not identical.

Somebody's fibbing somewhere.....

the 7-2's and 7-3's are somewhat close in overall sound, but the 7-3's have tighter, deeper bass, overall clarity is way up, more detail. If you can find a nicely priced 7-2, not one that has been messed with, you'll be very happy.
I can't imagine the said speaker working properly, different crossover, etc.....I'd pass if I were you.
Good luck!