Your right, apps on your smartphone will do the job, all that is needed is a precision accelerometer and GPS which most all smart phones have. I bought my 1st G-Tech back in 2000 when I was ramping up the power on a powerstroke diesel in my 8000 lb truck. Too hard for me to feel a 10 hp increase in such a heavy vehicle but the G-Tech could feel it. I later started using it for cornering Gs to find the limits of my cars. 2007 Mustang managed 0.84 G before rear end was sliding, Corvette got to 0.93 G before getting loose, and the Track-T I'm not sure but have recorded 1.02 G in the same corner but at that force the speed is so high that I might not be able to stay on the road when it breaks, so need to get to a deserted parking lot to find the T's limits.