There will be so many answers to this. In my testing, 87 Regular is the best bang for the (4) buck. Others have said premumn is better but I lost about 2 MPG over Regular.
And then there's that. ^^^^I have another thought regarding "the best fuel". I recall that I once bought a fancy pants, hi performance car and of course it required fancy pants fuel! What I discovered was that I was unwittingly pumping watery dirty fuel into my tank, fump filter, fuel rail and eventually injectors. How did this happen you ask? Well the gas was so darned expensive that no one bought it besides my dumb self. It sat and sat in the underground tank absorbing God knows what waiting for the moment I liberate it from it's underground ****.
So, the lesson I learned was to buy the cheapest gas from the busiest station you can find and be reasonably assured that the gas you are getting is fresh, clean and water free.