E85 is a very common gas to use for high powered street cars. Like Juicy K said, as far as tuning and timing, it is similar to 105 octane so you can run more timing and pull more power out of the same engine. The down side is that you get less MPG, and it takes more gas to make that power so you often need to put in a bigger fuel pump, bigger injectors, etc.
But as far as running premium in a car that isn't tuned for it, it makes little to no difference. The octane rating in gasoline basically tells you the amount of stored energy in that grade of fuel. If your car is meant to run on 87 octane and you constantly use 93 octane, you won't be getting the full benefit of the gas, the extra octane is essentially wasted because it is harder to combust a gasoline with a higher octane rating. The higher grade of fuel burns slower, and requires more compression to burn correctly.
The point I'm trying to get across, is that if you tune your truck to use premium gas (91 or 93), then yes of course use it. If you haven't tuned your truck for premium, you're essentially throwing money away by filling up with premium instead of regular. Vehicles have knock sensors to retard timing if they are knocking because you are using a gas below the recommended rating (say putting regular in a Ferrari), but they won't increase timing by using higher grade fuel. At least ours won't without tuning it to do so.
I only go through automatics in the winter.. All hand wash here bud. Plus i have my wifes car i keep lookin fly!
