100 kWh batterypack doesn't fit in M3?

[arnis]

If it has enough power to do the quoted 0-60 time it will easily haul an extra 400kg

0-60 is about acceleration and motor power. Roadster2 can easily tow a lot by pulling a heavy trailer (though hitch is unlikely).
But not carry on board. Roadster is not about practicality. Tuning suspension in the name of 400kg+ load capacity is not going to happen.

 

[FlyingKiwi]

Nobody said it would be ideal, but I guarantee if you put a bladder in the backseats and filled it with 400l of water your roadster won't implode, or fall to bits. It might not handle like its on rails, but nor will it randomly dive off the road into the nearest ditch.

 

[arnis]

Well, that depends on tire load index, springs. Actually camber might be wrong and grip might be compromised.
To the extent of ending in the ditch.
2 occupants of 160kg plus 400kg, that is definitely not ok to Roadster 2. I "guarantee" that