What are these Italian's like in stop-start traffic?
Absolutely fine, as long as the clutch and dual-mass flywheel are in good nick (they go very heavy and rattly when they are nearing the end of their life)
My average speed on my commute is around 30mph. When you consider that 18 miles of the 34 mile commute is dual carriageway or motorway, you can probably work out how much of it is in stop-start traffic.
Yes, an auto would be nicer, but its not a huge issue.
FWIW, the 159 came with an auto-box, but it isn't particularly refined - I'd stay clear.
You should definitely avoid anything with a Selespeed box. All the disadvantages of an auto with none of the advantages of a manual - nasty and often problematic