The sill covers for my 2.8 widebody were shot. Looked for ages to see if any used ones were any good (due to age, all had corrosion), then started to look for alternative material ones (plastic). I eventually found a bloke in the continent who made them, but no longer supplied them to the UK due to shipping and delivery charges (and in some cases damaged in transit).
So my only option for ones that were going to last me was to buy new ones direct from BMW. Ordered mine from Sopers BMW in Lincoln, and managed to get some discount for being a forum member. They cost me about £120 each (2 years ago).
If your Zed is a facelift 1999-2002, these were all widebody and these sill covers will fit yours:
If your car is prefacelift (1996-1999), it will either be narrowbody for 1.9 models or widebody for 2.8 models.
For widebody see above codes.
For narrowbody see below codes.
If your using used or new sills you will also need a fair few new nuts, bolts and plastic clips as most will either be rusted or snap during the process.