Test your new SCT X3 tuners before uploading a tune!
I bought my combo and uploaded the tune after installing the cai only for the display to die about 60% into the downloading of the factory specs. After a few minutes it did beep like it was done - and it was, thank dog.
I called SCT to find out that they had a batch of defective components that drive the LCD. They heat up and go out. American Muscle was good enough to replace mine, but still meant I have to park the car until the new unit arrives because I had to reload the factory tune to be able to use the replacement tuner.
Best advice - plug it in for about 5 mins or so and just play with it before uploading a new tune. If you have my luck, it will go blank. And you don't want that to happen during an upload - made my heart stop cold!