If you use this link you will see all the parts needed. this site is really good in that when you see a part used for an option (in this case S316A automatic trunk lid) you can click on the option icon and it shows all other parts.
http://www.etk.cc/bmw/EN/search/opti...ce/52150/S316A
Then you'll need to check rheingold to find how to wire the components together. The car won't have wiring already so you must create your own wiring harness and this also means buying the right plugs. This is not that easy since the parts diagram doesn't say what kind of plug goes into which component. Normally from the list of electrical components you can see large pictures of each plug and this should help identify the right plug.
Some of the wiring might also involve adding pins to existing connectors (not every pin is used in the existing connectors), but you can buy the individual pins yourself .. if you know what kind of pin to buy