I run the 93+X tune on my MKS because I learned of it when I read another thread. LMS did send a chart for me to choose from, but the 93+X wasn't available on it. Now reading this thread, there is an even HOTTER tune! Emailing Anthony to see what it'll take to run it besides race gas.
Edit - LMS told me that the 93 Stage 4+X and the 93-100+X are one and the same. The difference being the way it's named so that the owner remembers to run higher than 93 octane.