I've got a MY10-> S3 SB rear diffuser
Part number 8P0 807 434F 1RR
This should fit all models from MY10 onwards.
Currently sprayed in gloss black. Ideally if you want it to be mint, will need a respray.
Ideal so you can spray this one and swap or keep yours in original condition
I bought this for my MY12 model, but bought a RS3 item instead.