as anyone done rustproofing to their cars and was it worth it? I'm thinking its a good idea for winter but I dont want the additional weight.

 

I have the same problem my car is rusting very fast on the under side (I live close to the beach) the salt eats my car pretty bad! My buddy that details cars told be about a marine product made by CRC called Heavy Duty Corrosion inhibitor. I spray the underside of my car with it about every 3-4 months and it has been working well!! hope this helps.... other people should chime in with what other products that work as well