I was uncomfortable about tearing apart the dash on my 2014 tundra, but the instructions were legit. Took about 30 mins. I have a 6 inch lift with 35 inch tires. The first attempt i plugged in 35 inch tires, but the speedo was still off, so I measured them and they were actually 34.5. Plugged that in and now speedo is right on the money. As others have said I left the usb coiled up under the steering column, to easily access it with laptop anytime i need recalibrate.