The programmer downloads and stores the stock program (& VIN #) before you upload a program or modify settings. Once you have modified a program the 1715 "locks" itself to your VIN# and cannot be used on another truck until you restore the stock program on the vehicle you modified the programming for.

It takes about 5-10 minutes to change programs or settings, all you have to do is pull fuse #19 from the drivers side engine compartment fuse box, plug in the programmer and make what ever changes you want (turning the key on and off as the programmer prompts you) then put the fuse back in and drive away.