My 2002 Audi A-6 3.0 took in a TON of water in a couple severe rain/ wind storms this past summer 2007. I have had NOTHING BUT PROBLEMSwith it since. My brake (re-call taken care of) booster was full of water and the brakes FROZE on the road on a trip. Prior to that I've been going around with a mis fire in the cylinder (per my local mechanic) to the point it misfires so bad it is undriveable. After the brake deal and after they said my problem was I needed new tires (which I now have) my check engine light is on again (less than a week) from the 2nd. tow into Audi. My belief after much research is that it is catalytic converter issues. Possibly from WATER as I cannot stress to you enough HOW MUCH water this car took in - both engine and interior of car. I have YET to get Audi to direct themselves to the fact that ALL the problems I have had with the car is since it took in droves of water. With the amount of money $$$$ this car has cost me I'm quite upset not to mention it is my only source of transportation and since summer of 2007 it is not driveable more than it is!!!