Most stations here offer 87, 89, and 93 octane only. I'm not interested in a 93 octane chip because it would cost me too much money in fuel. But would an 89 octane program even be beneficial? I know most of the programs you do are 91 octane.

 

I can program for 89 but you'll find the performance and mileage gains will be half as much (if that good) as a premium fuel program. 93 tends to run the same price as 91 octane in most areas that have both so you're not paying more for 93 than places that only have 91. Basically, if you wanna play you gotta pay and the price is premium if you want the full benefit.