Pondered this all afternoon and decided to test this logical reasoning with Mrs interbear also
I reckon my throw-away comments have cost a fair number of people a lot of money over the years!
MY test drive a few weeks ago, seemed more refined than my current 2019 M3
Yes, I agree.
Higher seating position (preferred by some people, I'm agnostic on that); tunnel is higher to match, and that means that gap between tunnel and dash is less, and top of phone (on wireless charger) is visible on M3 but not on MY. For example, that has the next turn info in Waze
MY has EAP/FSD option instead of only FSD option on your original M3. Wireless mobile phone charging as standard. Tow hitch option (if you need that). Faster console CPU. Two "cellar" cubby holes in boot. The forward one is shallow, but fits the cables nicely. Back seats have 2 positions (I'm not sure I'd call it "recline"). Button to release the rear seats from the boot (to save clambering in to release the catch on the seat). Security glass at the back.
No parcel shelf. Rear-view mirror visibility poor - rear window, because of raked angle, is letterbox size/shape, and security class reduces contrast. I haven't actually found it a problem ... yet!
Under full-throttle (overtaking speeds) I find the MY a lot less precise, and the M3 behaves a lot more like a hot hatch. Not everyone drives like they stole it though!
M3 faster launch, but overtaking (e.g. from a steady 40 MPH) is within a whisker such that almost no difference. Bit less range on MY.
waiting a little longer given the potential for superchargers opening up
I've managed since 2015. Only used 3rd party charging on a handful of times, all of them dreadful, and a couple of other times which I tried and failed. I'm sure they are better now but current car has more range than the first, so I need Rapid Charging (for single day, longer, out-and-back trips) less than before (2 days a month before is now a couple of days a year), and there are more locations. If you already have an M3 not sure that changing to MY is influenced by waiting on more Supercharger locations?
I think that is some way off (actually installed in a car, and RHD model available). I've assuming I was going to keep all the Tesla's we've had for a long time ... actually something has changed to cause me to decide to upgrade. 20% more range; hatchback and towing instead of boot