no tune cai means no nothing. no performance ect ect. save your money till you can get a tuner combo, it will be worth the wait. no you dont have to run premium, but you can if you choose. you can get a custom tune( you`ll get 3 with the combo) of your choice. like 87 performance,91 performance, 91 street race ect. they are tunes writen for your car. if you add some upgrades, they can upgrade your tunes to get the most out of your car, milage, speed, power.

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goina hundred in a 55, and i dont know why..
some things were just meant to be..
05 V6 auto, torch red, basic,:cool: a few mods
06 V6 stick, vista, premium (g/f`s car)