I ride mostly urban, around sacramento and get over 100 miles per tank. Full akra setup with akra map. O2 sensors eliminated, but no power commander/tune ecu. Rottweiler intake with SAS block offs. I can slab to SF on one tank from sacramento. Ktm dealer setup the akra map when I got the akra pipes installed. They recommended not to use premium anymore after seeing how dirty my valves were, and use an additive instead. It's probably a theory on his part that today's fuel at the stations is full of soot from sitting too long in the tanks. He said he heard the same thing from his wife's BMW mechanic because her car was running like crap. So, now I run regular in both my BMW and my SD. The SD is running smoother than ever after switching to regular unleaded plus additive. I've used both startron and B-12 chemtool. I think the startron is a little better. Sometimes there is a little blowback on cold mornings using B-12, but that isn't really intended to compensate for crap sooty ethanol fuel. The startron additive seems to work best so far, maybe it helps boost octane a little so it all burns off before getting into the exhaust pipes even with the rich akra map. One little bottle will last 4-5 tanks. I haven't had any knocking from both the BMW and SD. Save a couple dollars at the gas station. Maybe you rich bay area folks can afford premium to keep it fresh in the gas station for those special days you're not driving the prius, but hardly anyone uses it up here in cow town. Just sit and watch which pumps the cars pull up to, even the geezers with the 750il and Mercedes 55 AMG won't buy premium today.