cambelt on V6, especially the tensioner, most leak if hydraulic, others can be fixed or use the 24v type wich are fragile by comparison.
2nd gear crunch and has it got a LSD, check propshaft is OK with no vibration at high revs (word of warning do not put your hands near it when running as it turns with the engine, pushing the cluth in will have no effect as its in the back, it will take your arm off if you are feeling the exhaust for a hole with the engine going)
can feel soggy by modern standards,
suspension: tired bushes everywhere, most parts fully avaiable though
largely OK, paart from thedreaded ARC warning panel, famed for being dodgy, eg: if the oil light stops on, check it has oil, but do not dismiss the car because of anything on the panel
the big one, body is galvanized, so largely OK with a few exceptions
1. red fades, so check it has not really pink and polished with colour magic
2. lacquer can lift and looks unsightly
3. front end of the car largely OK apart from around the heater box, hard to see, but leaves etc build up, stay wet and rot the metal in winter and catch fire when dry in summer.
4. rear of the car is where you need to focus, under the rear lights, the spare wheel well and boot floor, rear wheel arches are a weak spot as the plastic arches trap water. Sills go weak too, again hard to see beacuse of the plastic skirt covering them. Fuel tanks rust, especially if a 2.0 or 2.5 (3.0 is in the boot) so watch for leaks.
Certain cars have more desriable bits than others, eg skirts, bumpers etc some get recaros (2.0 LE and 3.0), others LSD (2.0 and 3.0 but not 2.5), aircon rare, sunroof more likely. 1.6 and 1.8s are rare. No too cars seem to be the same as Alfa seemed to put on whatever bits were available at the time.
Can be a money pit or a sound purchase, but either way be warned, it's likely to become an addiction.