[jmciver]

Well, FWIW, in the previous generation M3/M4 (F8x), there were differences in chassis firmware for steering, differential, traction control (aka MDM mode), suspension (for EDC cars), and transmission (for DCT cars) between different models/packages. Specifically, the M4 GTS, M4 CS, M3 CS, M3/M4 Competition, and Base M3/M4 (aka the "Civic M3/M4") all had different firmware in those respective modules (although some variants shared the same firmware on some modules, but different firmware in others - it was a mixed bag of sorts). In fact, there were some hardware differences as well between the different variants such as sway bars and springs.

Once the F8x matured some (and was "cracked" so to speak), it was (and still is) popular to update the various modules I mentioned above to the M3/M4 CS and/or M4 GTS chassis firmware for improved performance. I did this as well with my F80 M3 (Competition), upgrading to all of the M3 CS firmware stuff, which made a noticeable performance improvement, especially for the EDC suspension.

As far as the G8x is concerned, I would be surprised if there weren't similar firmware differences in both the chassis modules and some of the hardware (like springs and sway bars) between the different G8x variants. I think it is a foregone conclusion that the M4 CSL will have different chassis firmware and hardware. But it makes sense that there could also be some firmware and/or hardware differences between the M3/M4, M3/M4 Comp, and M3/M4 xDrive as well. Time will tell as the G8x is eventually fully "cracked" just like the previous generations….