I have owned mine for a year and it hasn't yet seen a drop of rain. Before that it sat in a garage for several years and executor of the estate I bought it from said his father never drove it or his other play car - an old Mercedes - in bad weather or much at all for that matter. It has a lot of undercoating on it from the dealer. The metal is all solid as a result - I've checked thoroughly.
I've only washed it once with water, and that was sparingly - just misted then clay bar'd and Zaino polished it. Now it's a damp towel if a spot is dirty but usually after driving it on the weekend I wipe it down with Zaino Z-6 to remove dust and to shine it back up. Stays covered in the garage during the week.
I sprayed the fenders, doors and rockers last year with Eastwood's rust product but I am preparing an all-out assault on the body cavities very soon. Here in the states the rust proofing businesses have dissappeared (Ziebart et al). The products like Waxoil and Dinitrol are expensive and hard to get and/or work with. I've decided to use Penetrol because it's readily available and I've read that Waxoil is too thick and the same Dinitrol that everyone uses in the UK and Germany is not available here (unless you want to pay $250 to have a gallon shipped over). I am buying a schutz gun to blast the stuff everywhere possible (a garden sprayer doesn't have enough psi to do the trick) and then make sure the bodywork drains are clear but coated. I've already re-routed the c pillar roundel drains out the wheelwells. I put silicone between the windshields' old gaskets and metal to keep water off those rust prone areas after treating it.
Living in a rainy climate like New Orleans and my plans to drive it to Oktoberfest in Birmingham - I can't expect to not hit rain at some point so I am preparing for it now.
I bought the car to drive - I give it the best shot against the elements as possible - but still won't purposely take it out in the rain.
