blah blah blah
never seen underbody rust yet!
but go ahead and rust proof it! its not going to hurt thats for sure.

as far as galvanized pannels go...bite me, all 4 of my doors have rust on the corner near hindge(never dinged, dented, chiped or repainted)
3 doors have the paint bubbling
1 quarter pannel has bubbling
and as far as i was concerned audi would fix this under warrenty, well they had my car for 3 weeks and didnt do **** to it, aparently audi canada is dragging their feet.
also i would like to point out i had to show dealer where rust was instead of them going over my car with a fine tooth comb. now the work order has been in the system for a month and still no word, and ive found rust that wasnt on the origional work order.

 

Maybe you shoudl stop washing your car with salt water.

 

oooh,
i thought it was good, like how the salt water pool is good for the skin...
"dish soap and salt water is the only way to clean ur ride"...pretty sure i read that somewhere

 

welcome to the board!

i don't see why ya would need to do it. audi comes with 12yr no rust on paint if im not mistaken. as well the metal is galvanized steel as well to prevent rust when ya have stone chips.

ps. 3m the the front!

 

I use Krown rustproofing on my car always have even with my previous car and they are really good kept my car looking like knew. I was told the same by the dealership that there is no need to rustproof but I still do too much salt on the roads during the winter makes me feel more comfortable doing it. Krown does put holes in the car but are covered up , like I said they do a great job.

 

Audi started galvanizing with the 86 model year
My 87 5000 is just starting to show a few minor rust spots. (bubble over the windshield and on a rear quarter panel. It's very slow growing due to the gavanization.

My 03 A4 has rust at the rear of each fender where stones not doubt opened up the finish.
Paint has now flaked off exposing about a 1 inch x 4 inch area of surface rust.

 

how can u check if ur rust is guranteed ....