Since I've run these numbers, I figured some people might be interested.
My aging dodge ram is a thirst trap for parts. I had spent about $900 on replacements in the previous 20k miles. Simple things like brake calipers and blower motors, no significant drivetrain repairs. I was not feeling the nickel and dime game anymore.
I can't not have a truck for my hobbies, so I looked at the old "get a beater DD" trope. We all know that doesn't really save money after you consider all the expenses, and the beater DD doesn't solve my nickel and dime problems.
So I started looking at new trucks. The capability of new gas trucks is good enough for me so I could eliminate the diesel premium and get rid of the repairs at the cost of... cost.
By my calculations, it was going to cost me $21,800 to keep DD'ing the ram for 5 more years. 60k more miles. Thats maintenance, fuel, insurance, and depreciation. Going for a new truck over those 5 years it would run me $27,100 over the same period. That honestly isn't bad... ~$1000 per year may be worth the time savings of not repairing things constantly. But the dollars don't really buy me any new features or capabilities.
So the M3... via a confluence of factors including lower per mile cost, lower insurance, and tax breaks, it is actually only calculated to cost $25,200 over 5 years to get the Tesla and keep the Ram. If that holds true, I'll be spending an extra $56 per month over that 5 years for the additional amenities which is fine by me.
6 months on, it was the right decision. YMMV.