Dissapointed, but has a use for some
It took my top end and put it down low, increased drive ability far as not downshifting and torque in higher than you have to be gears, but at wot in lowest gear lost top end, actually took .75 sec off 0 to 60, if you tow or have big tires and don't race, an could trade top end speed for low end torque it's for you, not for speed addicts. Low end mid range torque was very noticable but made truck overall slower
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.