You will have to buy a programmer. They will program only one vehicle at a time. To use it on a second vehicle, the programmer must be used to reset the first vehicle back to OEM settings.

 

Yup, what Ronjenx said. Buy a basic programmer and it will be worth it to adjust your speedo and tweak a few other things. You don't have to get something real pricey to install various tunes with. If you ever get to the point of regearing, you'll need one anyhow.

 

I used the AEV Procal Module from Quadratec, it was about 170.00, speedo is now within 1mph when I checked it against a gps/speedometer app. Went from a 225 to a 285 tire. There may be a cheaper alternative but for the ease and a few other things it can do, figured why not.