It is pretty insane that 4 people could order the same exact Tesla, same model year, with the exact same specs a week apart, and yet each person could receive a slightly different version of the car (one has no matrix headlights, another other 3 have matrix but 2 of the 3 don't have CCS compatibility, and one of the 2 non-CCS enabled cars doesn't come with the charging cable standard).
It’s part of Tesla's Agile production method.
Legacy automakers use the Toyota Production System. It replaced the Ford production system for many reasons, the most important was to increase consistency. The Ford production method had workers on an assembly line each doing their thing, and an inspection of the car at the end. Problems with materials or workmanship were noted on final inspection and these cars were sent back to be fixed. That was inefficient and expensive, and the percentage of cars rejected at final inspection was expensively high.
A main goal of the TPS is consistency. To this end, any line worker can stop the line if they find a problem. It empowers the workers, everyone is an inspector, the number of goofs that make it down the line goes down dramatically. The more consistent the output, the fewer cars actually need to be inspected. Pretty consistent, inspect only 1 out of 1000, really consistent, inspect only 1 out of 2500. This reduces production costs. The enemy of consistency is change, and TPS is pretty resistant to change. The design is locked one year before it goes into production, minor change at 2 years (change in shape of grill), more at 4 years, and so on until major model change at 6 to 8 years.
Production line changes result in more errors by workers, consistency goes down until they get used to the change. And since production is in a line, everything stops when changes are made. Counter to the goal of consistency.
Tesla operates in an entire different manner. No long production lines, instead production cells. Innovation and change are the driving forces. While legacy automakers fight changes, do small ones every 2 years, Tesla makes on average 27 production line changes per model per week. That's changes in the shape of the metal, changes in the electronics, etc. In one of Sandy Munro's teardown videos he found 13 design changes in the octovalve alone in only three months. The factory's AI computer knows what's in each individual car and so does the car's software. And computers perform every nondestructive test possible as a final inspection on every single car. Not 1 in 1000.
There may be several versions of the same part being made at the same time. One example of Tesla's Agile business, I think by Joe Justice, is that if an engineer dreams of a change to a part that would improve it by 2% or make it 2% less expensive to produce, he can send out an email the next morning asking for anyone who wants to help in in this project. He is given all the equipment and space needed to produce a prototype. Once that is done, and it is better than the existing part, that individual part goes into a production car. The AI computer keeps track of it. Then the next job is to ramp up production and feed more and more of the new part into the cars, replacing the old part gradually as the new part ramps up. Theoretically until the new part is 100% of the parts going into the cars. But that doesn't happen, because others come up with more changes and their better part phases in, then another, and another.
The production systems couldn't be more different. One is a model based on the past, the other the model of the future. A Tesla is a constantly evolving vehicle. One's expectations should evolve, too.
