all the sct tuners you can get custom tunes on it with out sending it in. I know the livewire is like that. i would go with the livewire over the xcal3. the evo you have to send it in to be able to get a custom tune. if you get it off american trucks you i think you get free tunes.
Thats the model I have, the SF3. You can order tunes from any SCT certified tuner, and receive your tunes via email. There is a USB cord that connects to your pc and the handheld, and there you go. Remember, the SF3 allows you to tune 5 vehicles w/ 1 tuner. Not sure if the Livewire will or not though.
Only mods I have on my truck right now would be shorty headers and single straight pipe. In spring I plan to add duel exhaust. Does that affect anything? Also, say down the line I lift my truck and have 35s on it. Would I need a custom tune or would the "performance" preset tune work? Other than adding duels I don't plan on doin other mods
for a lift and tires you dont need a custom tune. you can use the tuner to adjust for the right size tires. but to get the best results out the the headers and exhaust would be with a custom tune. if you use the can tunes (the ones that come with it) and you have some mods it can hurt the performance gains.
