No, the SCT tuner allows you to change your gear ratio if you switch out for different ratio gears. I think the gear ratio option is unlocked for the end user anyway, but maybe just make a note when you order with VMP that you need the gear ratio adjustment unlocked for when you change gears.

87 performance is tuned to get the most power out of the 87 octane fuel. 87 mileage is tuned to get better mileage out of the 87 fuel. I was told the mileage tunes are smoke and mirrors...However, some people claim to get better mileage with it. If you are getting 3 tunes, I'd go with a 93 performance (assuming you get 93 in your area, otherwise 91 performance), 87 perf, and 87 mileage. IMO, once you try the 93 perf, you are going to run that all the time anyway. It will be a kick in the pants. But if gas prices rocket again, it would be nice to have the 87 tunes handy.

Oh and make sure you get a USB cable if you don't have one...never know when you might want to order a different tune and will have to load it into the SCT.

Hope this helps.

 

Call Justin at vmptuning.com. He will answer all your questions & make recommendations. Thats exactly the tunes I have, both 87 tunes and the 93. I use the 93 as my DD. His 87 mileage seems to work great on my automatic V6 Mustang. I got27.6 mpg highway with my mods. Best with just the cai/tune/exhaust was 29.1 mpg highway. Best stock was 24.6. This is a great mod.

 

I decided to go with AFE cold air intake. Overall, it sounds great, looks good and had felt a 300hp difference..:P jk-jk. Nah, only a slight difference. My next mod is getting the Diablo Sport Predator Tuner. I'm thinking of getting it at Auto Anything because of the discount they give you after you buy a product. Have pics of the intake installed, but don't know how to upload them in the post.
Thanks