Doug DeMuro makes a strong case that the Tesla Model S is a mid-size luxury sedan, not a full-size:
So the Model S is sized like a midsize luxury sedan, and it’s
priced like one, too. Why doesn’t anyone call the Model S a
midsize luxury sedan?
Simple: because Tesla doesn’t want them to.
Tesla has fought incredibly hard for media sources to consider the
Model S a full-size luxury sedan, for one simple reason: Its sales
numbers aren’t as impressive if you compare it to more accurate
rivals. As I mentioned above, Tesla sold 9,156 units of the Model
S during the last quarter. In the same time period, Mercedes-Benz
sold 14,672 units of the E-Class. Meanwhile, the 5 Series sold
7,430 units of an aging model nearing replacement. When a
redesigned 5 Series last debuted, as it will again in the next few
months, it wasn’t uncommon to see sales totals well in excess of
5,000 per month — or 15,000 per quarter. Even the Hyundai Genesis
is nipping at the Model S’s heels, earning around 2,500 sales per
month through 2016.