Also, just noticed:
Tesla
*Curb Weight = weight of the vehicle with correct fluid levels, no occupants and no cargo
BMW
The unladen weight includes a 90% full tank and a driver weight of 75kg
So you can throw an extra 75kg onto the Tesla figures to make them equivalent to what 'legacy' manufacturers are quoting.
The top end of most of those ICE will be the PHEV variants anyway.
1970kg for the 3 series would appear to be the 330e PHEV Estate. The saloon is 1910kg.
3 Series ICE Saloon weight range is actually 1590kg to 1800kg against the Model 3s 1835kg to 1926kg (driver included).
So it would appear the lightest Model 3 is actually still heavier than the heaviest petrol 3 series saloon, the M340i, when you compare the figures and bodystyles on a more genuinely like for like basis.
I don't think anyone would argue that PHEVs aren't heavier, given they're carting around ICE and a mini EV drivetrain.
Edit - and to be charitable, going back to the original claim of 'The Tesla Model 3 Performance is lighter than the BMW M3' and using the M3 instead...
BMW M3 Comp Saloon xDrive - 1855kg
Tesla Model 3 Performance - 1926kg
I don't think the calculator needs to come out to decide which of those two numbers is heavier. I think blun has been suckered in by Tesla quoting driverless weights, much like the way they quote 0-60 with rollouts subtracted to make them look that little bit better.