Now when you say "increase the car performance" - yes it does. Electrical performance. Whether that translates into speed/torque/power I don't know. It really depends on the age of the car, how good is the ground, etc.
Paging Madman, paging Madman, please share your DIY radiator flush with coke here. I'm curious to know the history and reason behind using coke and how well it worked!