Am working with RS Tuning to determine what modifications of their DME would be required to run on US 91 octane fuel without risking detonation and engine damage. The person with whom I am working would like to run an engine dyno test using US 91 octane fuel but shipping gasoline to Germany is impractical. We believe that Euro 92 octane is equal to or lower than US 91 but RS has asked that I provide technical references, in German or English, substantiating this assumption. Anyone who might be able to help? Thanks you very much.