Heres what I found on
http://www.carbuyingtips.com/car6.htm:
Typical "Extras" at Closing
Description Your Price Dealer'sCost
Rust Proofing $800 $40
Don't buy the rust proofing from the dealer.
This is pure profit for them. They charge $800 and up for it, and how do you know if it's even on the car? Most cars have 6 year/100000 mile rust warranties, so you don't need rust protection. I've have a 1988 Trans AM GTA with no sign of rust. Tell them you don't want it, and if they say it's already on the car, tell them you're not paying for it. Wash and wax your car, you'll be fine. The salesman at Pontiac told me:
"But Jeff, you know the manufacturers just coat the underneath of the car with a quick worthless spray.
You really need our extra rust proofing which is much more thorough if you want effective protection"
Ah, the impending doom sales tactic. I told him that if GM does such a lousy job like that, I don't want the car now, at any price. I'm sure GM would be interested to know that stupid uninformed salesman are sabotaging their credibility. How can the squirt job that the dealer gives you be better than the factory's?
Don't buy the paint protection!
Don't waste your money on this junk. My friend who worked at a Chevy dealer said it comes in a $5 bottle. It's just wax, and they make promises about it lasting for years. NO car wax lasts for years. Read the warranty book for "Autoarmor", it says the warranty is void if you don't wash & wax on a regular basis. The salesman tells you it lasts 2 years or more without waxing. It's amazing how gullible Americans are, tell them what they want to hear, and they'll believe it.