Just finished full tank of premium 93 octane gas -according to the trip computer the V8 did 12.9 MPG, according to my calculation 245.1 miles/18.43 Gal= ~13.3 MPG.
I filled it up again w/ premium and will post the result as soon as the tank is finished

 

Looking forward to seeing the results. But in the end of this all, does 2 mpg make a significant difference?

 

yes, it does -assuming that annual mileage is 12000 miles, the difference between 11 mpg and 13 mpg is about 167 gal, at $3.00 it comes to about $500.00 annually. What surprises me is that it runs better on regular - I expected opposite.

 

If it runs better on regular, gets higher mpg on regular, and regular is cheaper, there's only one thing you could do - USE REGULAR.