Don't know how much Kah charges for them but are the really necessary in Singapore where cars are mostly driven for 5 - 7 years...? These days, car bodies are already galvanized and that itself already protects against rust.. then the point of rust protection systems pitch is, you are adding protection, but as far as I know, so long as there is even a crack in the protection, rust might set in, not matter what protection you have.
Any inputs? Thx.