Installed mine last night. It took me about 4 hours. Most of this time was spent cleaning up the M3 base ring as it is bonded to the M3 boot very securely. The other big chunk of time was from repeated attempts to trim off new boot leather from the ring so it would snap into the console. Now, I glued and actually didn't even leave boot tabs over the ring clips, so that wasn't the issue. The issue is that the M5 leather is thicker as others have mentioned, especially where the boot is sewn. I never managed to get a full seat and engaged clips into the console (even removed the console trim to try). So, the two clips at the rear are in but the two toward the front aren't. The boot is secure enough due to the press fit with the thicker leather, just not locked tightly with clips. Overall, I would have taken greater care to align the sewn seams with the shallow notches in the ring or simply transplant the knob only.
However I am still very pleased with the result as it looks great and feels excellent...better on the 1-2 shift (but still not perfect).