Nah. On my 96 GT vert I shift around 2500. Tires shouldn't matter depending on size and even then it wouldn't be off that much. Right now I only have intake but I still shift the same. For best gas mileage, just make sure to put into the lowest gear that you can cruise in. Usually if I'm cruising faster than 40mph I am in 5th. But when you get to up hills I tend to down shift so I'm not stressing anything.
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