Modifying modern cars for high performance impacts the emissions systems. In many cases the ECU modifications will actively defeat certain emission control measures to allow the higher power output without check engine lights, for example.
Showing a good faith effort that you've designed the emission compliance systems to be reliable and hard to defeat is part of the process.
There's a similar thing that happens with WiFi access points: You have to show that you've made an effort to prevent the end user from trivially modifying it for higher power output or other changes that would deviate from the way it was compliance tested.
Modifying modern cars for high performance impacts the emissions systems. In many cases the ECU modifications will actively defeat certain emission control measures to allow the higher power output without check engine lights, for example.
Showing a good faith effort that you've designed the emission compliance systems to be reliable and hard to defeat is part of the process.
There's a similar thing that happens with WiFi access points: You have to show that you've made an effort to prevent the end user from trivially modifying it for higher power output or other changes that would deviate from the way it was compliance tested.