prof - I believe the 2.4 has an MDF baffle, as the model 2 has had from the beginning. Whereas earlier 2s had 2" thick, I think the 2.4 is 3" thick like the 3.6. beetlemania knows, he has been in there.
The baffle is one thing. Another is that the 3.7 XO is all high-quality film caps in all feeds and the only electrolytics are in a resonance / shaping circuit of the midrange and tweeter, which is the most benign place for them and they're bypassed with the custom 1uF styrene / tin foil cap. The 2.7 adds a 400uF electrolytic feed cap in the midrange feed. But it is bypassed with a 15uF PP and the 1uF styrene / tin. That electrolytic feed probably does a little damage.
Then there is geometry. Looks aside, the 3.7 aluminum nacelle rocks from a functional perspective both interior and exterior diffraction. And as you say, the aluminum baffle. More budget for the 3 than the 2. Our 2.7 hot-rod will replace all electrolytics with custom ClarityCap CSAs. We'll compare sonics for cost efficacy.