Have you looked for proof, or are you waiting for it to just fall into your lap...I see the light bulb didn't go on in your turnip patch...do some research...you'll see

 

I do not run premium, the manual says 86+. I just listed premuim cost b/c my car requires it and that's what I bought last. Don't waste your money on premium for your bike- unless it knocks. Premuim is not better, just stops knocking. You should get better milage with 87 anyway.