Due to a hurricane in our area I have been forced (by a gas shortage that has lasted for 2 weeks now) to use 87 octane fuel. Premium is simply not available and we are lucky to get regular. I was pleasently surprized by the performance with the 87 octane JLT tune. not right on par with the 93 tune but close. I was able to add 2 degrees of timing to the 87 tune with no problems. My gas milage has droped by 1-2 MPG though.