[karmat]

No, adding more paint won't help, unfortunately. I lived in Ohio for a long time and had Alfas there. They do rust but if you're careful you don't need to worry. The main things are in how the car is used. Don't take the car out during the winter. Wait until at least two good rains have cleaned the salt off the road in the spring before driving the car. Clean out the wheel wells behind the riveted panels (drill the rivets and replace them with screws). Wax the car religiously and when you wash it, spray off the whole underbody as well. When a nick in the paint appears, touch it up immediately.

Rain is not bad for cars if you don't have blockages causing the water to pool anywhere. The worst thing it does is kick dirt into places that can later retain water and form mildly acidic paste that then eats at your car.

Keep things clean, don't drive it in the winter, and make sure the salt is off the road before you get it out. Resist the temptation to take it out on the first nice spring day when the road is still white with salt.

Lots of Alfas live in the mid west and survive the salt by staying out of it.

A good cavity wax can help keep internal rust from eating things. Wurth makes a good one in aerosol cans.

Cheers,
Karl