Has anyone had any experience with this shop for tuning? My car is currently tuned for 93 octane and I need to get it bumped down to 91 octane. Called these guys and they said around $550 for a fresh dyno tune. Does that seem to be about the going rate? Also do I pretty much just run my car out of the 93 octane gas I have in it now then fill up on 91 before the tune?