Having worked for two automobile manufacturers in the past, I can say that some of the wilder prices do not come from the dealers, often they are created by the OEM manufacturers and the retailers will simply charge their retail price.
When working for these companies, as part of our work, we would quarterly, at the behest of the parts reps, look at particular parts pricing and do comparisons to competitive and non-competitive makes.
For an example, a particular car had a fender price that was three times more expensive than a competitive car. The factory worked through to margin average the parts price. Then again in another comparison, a windshield was $125 less than an "economical" import and the price was raised.
We learned that certain landed parts costs were insanely priced for a variety of reasons. Often, beyond the uniqueness or its value. Typically if a part can only be sourced from manufacturer, then its price is going to reflect that, but within reason. Some parts when associated with important structural features (safety for an example) and liability issues, would be priced more.
The cost of the infamous illuminated sun visors .... everyone knew they should cost about $30, but were being sold for $350! Over a period of time most manufacturers not only matrix prices, but also look a volumes and finally a realism test. This is what finally brought the $350 sun visors down.
The after market and the grey market competition really woke up a lot of European manufactures in the late 80s and early 90s. Although there are many views and sides to the grey market parts systems, generally it can be said that external part supply competition has brought prices on a lot of parts back into line. But not all ...
The quality of the parts also played an important role. If the part was going to be installed, would it survive the common 6 months or 6,000 repair service warranty, not to mention meet all performance criteria.
I have no axe to grind here, I do not work for any manufacturer of automobiles any longer. I thought I would simply share a bit of an inside view into the true pricing process.
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)