Thiel 2.3 vs 2.4 the real difference

What parts can you upgrade from 2.3 to 2.4? The passive radiator is oblong on the 2.4 and round on the 2.3, right? I know there is an upgrade on the 2.3 that I haven't gotten which includes new coaxial drivers and changing a few parts in the crossover network. An older Audiogon thread says the upgrade is an improvement.

The tonal balance is quite different between the 2.3 and 2.4. The 2.3 still has the older Thiel hyper-analytical sound; the 2.4 retains the best aspects of that sound but leavens in a degree of warmth missing from older Thiels. Certainly worth a listen in person-- if going back to Thiels (I had CS2s for 16 years before moving to Vandersteens) I would definitely choose the 2.4s: they're a kind of middle ground between the older Thiel sound and the newer Vandersteen sound (perhaps a third of the way over towards Vandy warmth).

Bufus
'Upgrade' I mean selling 2.3 buying 2.4. Hope you got it now..