The octane really doesn't do anything that noticeable as far as performacne goes, even racing blue, doesn't really effect it all that much. However, it's going to be along term thing, you aren't going to notice it immediately as much as you will over the long term. For example, if you continuously use premium gas, you'll notice that your car will shift smoother, knocking will be eliminated, and your car will accelerate quickly and quietly. You'll be able to tell a substantial distance in performance after a good 2 weeks of use, just because your fuel system will be cleaned out, and the better your fuel system works, the more efficient it will be.

You have to keep in mind that most fuel systems are running at a fairly high capacity for what they should be handling anyway, as upgrading the fuel system is quite expensive. So, keeping that in mind, you should take good care of it, and use only the best fuel possible. I always use premium fuel and I add fuel injector cleaners and that sort of stuff on a regular basis just to keep it running efficiently. Try adding in fuel injector or fuel system cleaner and I gaurantee after 3 full tanks of use, you'll notice a beautiful difference.