This article shows an extensive maintenance for the rear suspension. It is a good practice to have the suspension springs replaced as these loose their properties over time.

The parts needed for the rear suspension are just a few.

New springs, flexible tube to protect the first turn of each spring side and rubber thrust rings which sit between the shock tower and spring.

Here is the part list along with the Alfa Romeo original part numbers:

Spring thrust rubber ring (left side) 60590867
Spring thrust rubber ring (right side) 60501917
Front spring rubber tube 60501921