2nd Eurotek groupbuy

Being that California is the only state (to my knowledge) that has 91 octane hi-test (instead of 92 and 93 in others), most manufacturers design their cars to meet the 50-state requirement (91 octane) and most ecu / "chip" companies design their products to make use of the extra kick available with the stronger fuel (93). That's where they get a good deal of the horsepower from. So if you're in CA and can only get 91 (like us), ECU mods are generally a waste of money because the ignition will just be retarded back anyways -- unless you can get one that was specifically designed for 91 octane. Those generally don't have spectacular results, as the manufacturers designed it to run on 91 in the first place.