The Pininfarina designed and built Peugeot 406 Coupé was an example of a car where nothing ever stayed the same. The entire model was used as a production test bed, and there were constant revisions to the components. The cars had Exhaust Gas Recycling systems and Particulate filters on the diesels which weren't required for another 3 or 4 years because Peugeot wanted to test it out before they put in on their later model ranges.
Even if you had the same year, trim level and engine there was no guarantee that the cars would be the same. A case in point was the centre consoles which changed numerous times (mine had cup holders, another didn't) and the door pocket liners (I had carpet, others had rubber). 2002 models had auto-window up/down control from the keyfob. Earlier and later ones didn't. I actually liked this feature because it meant I could climb out the window in tight parking spots, lock the car and put the windows up, and vice-versa to get back in.
There was a refresh which we called version 2, but between version 1 and 2 was version 1.5 with some of the new electronics on a modified older loom. I think some of these half-MUX v1.5s were limited edition models (Black and Silver) which had some items found on later cars like auto headlights and wipers, but no self-dimming rear mirror. The dashboards were different between versions too, so the in-between cars were a bit mix and match parts bin specials. The blue painted ones were very pretty - especially with cream leather: like something off a tropical beach; but the colours also never really stayed the same either and there were a number of different ones over the years and even the red had a few different shades.
The car was sold in such small quantities that it didn't even qualify for a Haynes manual. We ended up having to pretend to be a garage in order to access the official Peugeot Dealership system (on a Win XP laptop no less) for the technical diagrams and parts numbers.
Yes it was a bit annoying when you were trying to find spare parts (thank goodness for breakers' yards), but it was a beautiful looking car, and lots of fun to drive, especially after you remapped it. A Tesla Model S is probably one of the few cars that I'd think of as a real replacement for it.
To tie in with this thread the rear seats were amazingly comfortable with deep leather buckets and space that could easily accommodate the 6'+ person with comfort and space for both head and legs. Another note on seats, the top spec models obviously had full leather, but the Silver and Black editions only had half leather! Also some leather combinations were... interesting. The first time I saw the full red leather interior was, well, I guess it was very much about personal taste.
Should never have sold mine really, but boy was it a money sink
I think I replaced every part on the car at least once. Such is the fun of driving a test-bed.
I think the differences just made it more exciting when you came across that real rarity: another person driving one of the 10,000 or so cars made, and got to see what they had in theirs!
I would expect that there will be a burgeoning 3rd party parts market for Teslas in the coming years and more and more people will swap in and out differing seat styles, trim levels and accessories. So perhaps going forwards you can have your cake and eat it.