Cd head unit & rear blind

[ro66ie]

I've now had my 95 a8 now for 3 months, and just recently the reAr blind has started sounding like a machine gun when it lowers and settles into it's down position,It makes the noise for about 10 seconds after it's settled,the blind moves freely so don't think it's anything above the parcel shelf, also does Anyone know which, if any audi cd head unit I can fit inplace of the tape player head unit which is in at the moment. I know i could fit an after Market unit but want to keep the car original as much as possible at the moment
Many thanks in advance for any help