Are you 100% sure that you're going to swap out the S for a 3?
In my opinion: if you're worried about depreciation then it seems to me the sensible thing to do would be to just get an S and keep the S, as opposed to buying an S, selling the S in a few years, then buying a new 3.
It's interesting how the different threads look.
On Carter's thread, most people recommended buying new
On this one: most are recommending buying used.
I don't think it makes sense to buy a used car if the price is anywhere near the new car, unless the old car has EVERYTHING you want, and the new car lacks something.
If you're deciding between $54k used car with everything and a $67k bare bones new car... the $13k is compelling
but deciding between a $63k used car and a $67k new car?
not so much.
especially if the used car has things you don't want (21in tires) or lacks things you might want.
It is true that New Cars depreciate faster than used cars
HOWEVER: the new car has things that the old car won't. (Autopilot, new fascia).
my guess is that the old fascia cars without autopilot are going to start to depreciate like crazy.
think about it this way... what's worth more in Jan 2019:
-a 2 year old 2016 car with Autopilot and current fasica?
-a 5 year old 2013 car without autopilot, and old fascia?
in the end, you should go with your gut.
trying to make a "wise" financial decision when buying a luxury product is a mind numbing exercise in futility!
The wise financial decision would be to baby your current car, or to buy a Volt or the new Prius Prime!
(I think the Volt is AWESOME).