Alex, most revisions I do is to finally break out girl in you and be a man. In other words, after working with Xtreme customers, I apply that change(s) to those who should have adjusted. Example...better aggressive throttle, better and firmer gear shifting and holding. Different in sound etc etc.
In addition, sometimes in tuning, a customer do not have much time and close analysis shows you that you can extract a little more from some areas. I apply these changes to future tunes and sending out updates to customers who could appreciate them.
As per usual because I drive you always look for that extra to feel you can do more