I've used 87% for the last 5 fillups, and I haven't seen any change in gas mileage, performance, or noise. Has anyone else tried the lower octane gas and had different results. Thanks, Bill. 90% of my driving is highway which I put on cruise control at 55 and stay in right hand lane, and am gettting 30.4mpg highway, 10% intown I don't use a/c and get about 22mpg. Need feedback on regular unleaded as opposed to premium octane. Thanks, Bill.