I did some experiments last night and this morning. Any parameters I change in the custom mode will persist; display color, torque, traction control, regen, everything... but the max speed always reverts to 108mph. California is not open yet, I will call for help in a couple hours.
Don't be so quick to judge how fast I should be riding. I've been commuting on two wheels for almost 40 years and I'm still here.
On the portion of my commute I was commenting on, its a wide open highway where the average speed of everyone ranges from around 85 to 100 mph. Mom wagons with cheerios on the floor are sailing along faster than many people ever go. And in this part of that highway, the road has been straight and open with clear visibility for almost the last mile, so speeds pick up even more. That's the way it is. Such places do exist in the United States. Its not out of line at all to need to speed up to , say, an increase of 20mph vs the traffic just to get a spot to exit, and suddenly with no warning I was unable to do it.
On a road like this, having my speed limited to 106 is a liability. It limits my mobility to get out of people's way as well as to get where I want to go.