be careful, there are two different lengths of that hose...whether you have the early rod controlled throttle, or the later cable controlled throttle.
I am guessing yours, being an S3.5 1990MY motronic, will have the rod control (I believe this is nominated C9777 in the parts book)
so before buying ask for measurements, especially when ordering from abroad as shipping to and fro sometimes is a hassle (and the suppliers won't pay for your mistake and will rarely admit to theirs

)
two PNs were (and only go by these if the hose is in the original AR packing, because many suppliers just quote the first PN that comes to hand....)
60520972 (variant: C9777)
60564746 (variant: D9777)