I too planned on buying my first M3. But depending on how autonomous the initial M3s will be, and other features, I may lease my first M3 then after that is up buy a M3 and keep it longer. I generally keep my cars 8-10 years, but my Acura ICEs haven't advanced much whereas Tesla is constantly innovating. I'll have a better idea after the second announcement on how I will finance my M3.
While supercharging my X in San Mateo on Saturday, I spoke with a very friendly member of the autopilot team who works on computational modeling R&D. I noticed the S he was driving had metal, unpainted, ultrasonic sensors on it. I forgot to check his front camera - I was near the end of a long roundtrip road trip to Ukiah and I was a bit dehydrated. Hope I'll run into him or one of his colleagues again!
Anyway, one of his comments to me was: [1]
"There is lots of low-hanging fruit in the EV space" - meaning there are many innovations that are relatively easy to accomplish from an engineering viewpoint, since EV technology is still in it's infancy, compared to 100+ years of ICE. My personal take on it is a 2026 (2021?) will make a 2016 seem quite obsolete. I'm happy I leased my X.
It does cost more in interest, which is ~4% now based upon the money factor, compared to 1.49% lowest I've seen reported for loans.
While I was there, another Tesla employee with his girlfriend(?) stopped by to supercharge his company weekend loaner.
My theory is the autopilot/autonomous team has free use of test and production vehicles over the weekend so they can drive Alpha and R&D code in the real world.
[1] At the beginning of our chat, I specifically asked him not to mention anything to me that's Tesla Proprietary, and he did not. As we all know, sales is kept totally in the dark about the pipeline. I did learn that, unlike the big fruit company building a spaceship, there isn't a firewall between projects internally among engineering.