The Model S is the oldest Tesla vehicle still in production — but with a new range upgrade. Here's why it might still be the best. (TSLA)

· The Tesla Model S, the company's oldest vehicle still in production, recently got a range boost, to 402 miles.
· That's almost double the range that the Model S launched with, in its least-expensive version, in 2012.
· As the Model 3 and Model Y assume the bulk of Tesla's sales, it's easy to forget about the company's...