The highest octane I can get in New MExico is 91, but thats what I always use. I replaced the fuel filter and am going to get a fuel injector cleaner. The garrett chip will take me all the way to 7300 if I go slow, and yes the stock redline is 6200ish. ??? I have a free fuel pump that a friend is going to send me, so I won't be out any money. thank!! Matt