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.

Cinematic Systems, could you describe the measurement technique used to find that "the CS2.3's are +10dB by the time they get to 20khz and +15 to 18 dB from 1 khz depending on the individual speaker" ? Were these your personal findings, etc.?

Cinematic systems, what piece of equipment did you use to measure the speaker's response? What weighting did you use?