This mod is very simple yet very useful. It does one and only one thing: remove the taillight flashing on heavy braking with the ETK 800 and K-Series. Nothing more, nothing less.
To disable the flashers on these cars, simply select "ESC/TCS (No Flashers)" in the vehicle customization menu.
Yes I know these flashers are legally required on cars sold in Europe. Still doesn't make it less annoying in-game.