there are a few online people that we deal with - the ECS is the board sponsor, there is Pelican Parts, KO Performance, BavAuto just to name few... for the part numbers i suggest using RealOEM.com - you punch in your last 7 of VIN, and then go through the categories to see the parts... also, there is bmw-planet.com, with electrical schematics, and also bmw TIS (i don't remember site's URL) with repair instructions... a lot of us have factory PDFs with retrofit info... also, check sister sites, a lot of things are same between the cars...
well... welcome aboard...
hopefully you will enjoy your ride...