From BMW ask for the pre 1998 E39 "Aerodaynamic kit" Do not ask for the "M" aerodynamic kit, that's the M5 stuff.
It's exactly what I have on mine though I may have bought the last one. There was endless screwing around by BMW ZA to locate one in Germany. I bought the kit, front and back clip and side skirts, was about R11000 four years ago
If you need the part number PM me.
Buy the ebay one at $220 (R1540) it's a lot cheaper than BMW will nail you.
I have to admit the genuine BMW one as I bought from BMW (and actually made by Zender) fits to the exact mm