I have a suggestion Mike.
Can the car be programmed to the speed limiter in CCC/CIC. This way one can limit the car to whatever speed ... it can be 65, 90, 120 etc. So switch off the gong for the speed limit and have a dynamic speed limiter. This will be a discreet function and the dealer stealer or the valet (or your girl friend) wouldn't have the first clue.
When you get in the car switch off the speed limit warning, and now you have a normal ///3 for your driving pleasure.
This is also a good function to have when driving in city limits so you don't exceed the speed accidentally.
I can remember driving an A Class as a hire car during a work trip to UK a few years back, and you were able to use the left stalk to set whatever speed you want, and doesn't matter how much you try to flog the car, it will not go beyond that speed limit.
I know you have already spent countless hours developing the valet mode. This is just an idea to eliminate flashing each time.
I would love to hear your thoughts on my idea ...