The only people that pay 100’s of thousands would be NASCAR, formula 1 and some rich people from the likes of Saudi Arabia or Texas oil tycoons. Realistically people pay 10’s of thousands for extras performance. However, they all buy physical parts. My point is that for 8k all you get is modified code with the same hardware. The cost of the software just isn’t worth it FWIW IMHO.
Modifying that software is not a trivial matter. You don't just change some parameters and call it a day. You do some modelling to determine how to change the parameters, then you have to do simulation testing, then your have to roll it out to the test mules and make sure the car can handle the power changes in the real world. And you want to really test it to ensure you know where the new corners now are. And all of this must be accomplished with the confines of safety and reliability because kill or injuring people is expensive, and so is breaking the chassis with too much power or power added too fast. And any one of these steps can lead to a complete redo of all of the subsequent steps.
It actually is not all that different when you change real parts these days. You still simulate everything in a computer long before you cut metal. Then you modify the code that controls the power curves, since everything is computer controlled. And then test as above, iterate, and test some more.