I see what you mean now! Because we have the entire BMW parts catalog (or close to it) searchable on the site there are millions of parts available! Some parts have not been described and applicated to vehicles for this reason, for instance the Center Armrest (52208257757) is available via one of our parts warehouses but we have yet to add information (vehicles it applies to, description, etc). Some parts such as the carpets (51478227522) have simply not been applicated (had the vehicle attached to them so you can navigate to them via the categories). I have 2 BMW Parts Specialists who applicate (describe and "attach" to vehicles so they show up once you've selected your car) parts all day. We do this so you get the most information and the most accurate information possible.
We do have a massive selection of rare parts (especially euro market parts) if you ever question the parts availability you can always shoot me a PM and I'll call up our contacts at the parts warehouses and confirm the parts are available, or see if I need to source them from Europe for you.