certify, before you start to buy any parts you need to do some more research. The basic parts you need are some nut/bolts/screws/brackets/cable ties. The main parts are the Nav (I guess you have the MKIV?), GPS antenna and it's cable called cable "B" (these are cheap on ebay and I have a lead for that) you can also get them from the dealer at higher cost, the main adapter cable called "A" in the instruction PDF (the P/N listed for the kit is for a MKII/Trimble GPS module and there is a different P/N for the MKIII/MKIV and I think it is 61 12 6 907 844 and should still be available at the dealer). the separate GPS recever module in the parts list is not needed as your nav has a built in GPS, NOW the big question is whether you actually need the "C" cable. Study the instructions carefully and maybe get a WDS wiring diagram DVD or wait for some comments from this board. Kiwijochen is very familiar with the RHD e39 and its wiring and probably can tell you. There are more wiring diagrams available on bimmerboard for the full retrofit kit of a nav and TV for the MKIII (MKIV).