Beyond the structural sills and floors, the Giulia Spider rusts in a set of predictable outer-panel places. None is as serious as the structure, but they tell you how a car has been kept — and they are expensive to put right well.
The front wings
Two spots matter: the bottoms of the wings, where mud and salt collect, and — less obvious — the tops of the front wings, where mud lodges and works away out of sight. Bubbling paint on the wing tops is a common Alfa tell.
The doors
The lower insides of the doors rust from the inside out as the drain holes block and water sits. Bubbling along the door bottoms is usually the first visible sign. Open the doors and feel along the bottom edges and inner skins.
Window surrounds
Rust can also work out from the trim around the windows, where seals age and let water sit against the metal. Look along the screen and window frames.
Reading it
Outer-panel rust is less structurally alarming than sills and floors, but it is a good barometer of how a car has been stored — and original panels and good paint are costly to restore. A car bubbling in all these places has usually been damp for years; treat it as a guide to what may be hidden elsewhere.