rusty arches are caused by stonechips that remove the galvanised layer. you also see it on sills where the same thing happens. if you regularly touchup all stonechips then it wont happen.
ive never had this problem with any of my bravo's and ive had 4, 3 of wich were 100,000 plus miles but i wash my cars every weekend religiusly im afraid, you get what you give with fiat like alfa if you dont take care of it it will just turn into a shed very quick lol.
hehe, i'm working on it.Jug get that bl**dy Vauxhall off your drive and out of your sig... it's making our members do silly things