[Jackpine]

X2 - but naturally I have to add to JHeppner's post!

Virtually every person who's tried the high octane tune has said he got more power and better gas mileage. If that's all you're interested in, fine - go to it.

If however, you are asking will the change be "worth" it, things get more complicated. Power, of course is something only you can judge, and if it makes you happy, it's all good. If though you are concerned about the extra cost of fuel and are trying to actually save money, you have to do some math.

I buy gas at Costco and regular here is $2.23 (right now). I'm pretty sure 91 octane is about $0.22 more. So using the price of regular as a baseline, 91 costs about 9.9% more to fill up. If your mileage improves by at least 10% at these prices, it would make sense to by the high priced stuff. Your highway mileage would need to be 18.7-19.8 to make that come true.

Can you get that much improvement? I don't know. I've never tried.

- Jack