The x.7 drivers are indeed breakthrough design. That said, the 2.4 drivers are very mature and made and tested in Lexington with significant, advanced technologies. The 2.7 cabinet is stiffer, but the 2.4 will come close in vibrational performance, especially after tweaking. Regarding passive component quality, the upgrades will leap-frog the stock x.7 series into pretty rarified territory. We can expect some veils to be lifted by applying technologies that were out of reach for the stock product line.
FYI: I have contacted the world leader in audio cryogenic immersion. I am previously familiar with what can go right and wrong in that process, and how to stay out of trouble. I will be comparing stock and cryo-treated crossovers to evaluate efficacy.