Another thread discovered the Land Rover Discovery rear view mirror fits the x308 perfectly - what other seemingly-proprietary parts are swappable?

 

The indicaator sockets are standard VAG parts.
The transmission filter on N/A cars is the same as in most 5 speed BMWs.
Front wheel bearings are rhe same as in the PT Cruiser.

 

I think the sway bar links are Opel ... the Fuel filter is a common GM filter.

 

The window switches are the same as in some Ford models, the brake pedal rubber is a Ford part, many of the connectors and relays are Ford Branded and so are a few of the modules. The rear parking sensors are VAG (Volkswagen Audi Group) as are the marker light bulb holders.

You will find that many cars have parts from other manufacturers fitted as a normal thing, for example the 1990 Aston Martin has Audi 80 Headlights and VW tail lights. The MK1 TVR Cerbera used Ford Fiesta Mk3 Tail lights, The Aston Martin DB7 shared a lot of it's dash switches with the Fiesta MK4 and Escort MK6/7. Many of the parts on a Rover 75/MG ZT can also be found in the BMW parts catalogue owing to their ownership of Rover at the time of design. And even though the New MINI is made by BMW it was designed by Rover and BMW took it with them when they sold the company, which is why on earlier MINI's a lot of the parts are the same as found on Smaller Rover models.

 

The rear ones are Ford parts. From the Mondeo (should be Ford Contour over there, if it uses the same rear axle) MK I/II.