Tesla Motors only reveals its production figures every quarter, but it has now likely built up to 90,000 of its all-electric Model S luxury sport sedan.
The company also doesn't group its changes and updates into model years, but makes running changes in the cars whenever the updates are tested, validated, and ready to roll.
So how is a Tesla Model S built in October 2015 different from the first one sold to a paying customer (actually a Tesla board member) in June 2012?
DON'T MISS: 2014 Tesla Model S - Full Review
The shape is still the same, and there are still two battery-size options, though they have risen from 60 and 85 kilowatt-hours to 70 and 90 kWh.
New performance options have been added at the high end: A "Ludicrous" performance mode has joined the "Insane" mode pioneered on the P85D.
All-wheel drive "D" versions are now available, based on the dual-motor system developed for the Model X crossover utility vehicle first delivered last month.
2014 Tesla Model S in ChinaEnlarge Photo
But under the surface, there are a surprising number of updates, additions, and new features, many of them additional-cost options.
Our thanks to Tesla communications staff Alexis Georgeson and Shanna Hendriks, who patiently compiled a list of all the hardware and options changes made to the cars since the start of 2013.
[EDITOR'S NOTE: This article was first published in June 2014; we have now updated it to reflect additional Model S updates from that date through October 2015. The new material is throughout the article.]
This list doesn't cover Tesla Model S software changes, of which there are literally dozens, grouped into minor and major releases that are pushed over the air to the car once the owner gives permission for the update to occur.
Tesla owners will undoubtedly flag any hardware features we've left out, described incorrectly, or otherwise gotten wrong in the following list--but here's what Tesla Motors sent us.
January - April 2014
2014 Tesla Model SEnlarge Photo
January - December 2013
"It should be noted," Hendriks wrote, that none of these are mandatory changes--they are merely options that have been added to the roster" of available equipment when ordering a new 2014 Tesla Model S.