This problem has become a common occurrence with my Alfa 147, and just finding this thread has given me relief in knowing that other people have experienced the same problem as I have.
At first I believed the problem to be some foreign object stuck to the undercarriage of my vehicle, but after inspection could not see anything obvious. Secondly, I thought the problem was the tyres and that in some they were slight deflated or losing air causing the car to ride uneven over road humps, because in some instances, the very sever bumps are when you can hear the scrapping effect.
Only when I crawl over them do I not hear such a noise.
So I would just like to know that if that accessories part form Auto delta is an easy solution to resolve it or stiffen the springs would remedy my problem, because it getting on my nerves and feels really disconcerting when you hear it.
I have plans to do amendments to my car like I have seen other users on the forum do to there Alfa:
exhaust tip, wheels, etc.
but firstly this is what I ned to do to keep my mind at peace.