Always run 93, do not put in 89 or 87.
Nearly no gas stations just carry race gas.
If you go to the Track, there should be a gas station there, or nearby with race gas. Run the Race gas when you are doing a 1/4 mile run. Not on a daily basis, unless you can somehow afford $8.00+ a gallon.
Here's your other option, E85. E85 is like 105+/- octane rating and is cheaper than pump 93. But to run E85, you need a larger fuel pump, bigger injectors, and a tune. Not to expensive to switch to E85 and the gains will be phenomenal. The tough part is finding some one to tune your car for E85.
If you do the E85 conversation, your MPG's will more than likely drop. Maybe 3-4 Mpg? It varies. But the performance gains from it are great.
