4) I couldn’t really get a true sense of the performance as they gave me an M3P service vehicle locked in chill mode. I know it will be fine though.
It sounds like you have a fantastic basis of comparison with your ownership history. My history includes many sportbikes, an Abarth, a smart car (heh), two Honda Civic Si models (2002 and 2005), and nothing much beyond that.
Chill mode is almost worse than not driving the car at all. Performance in sport mode is a whole other world. You can adjust the feel of the steering, from 'comfort' (default) to I believe 'standard' and 'sport'. There's also track mode on the P cars, though I don't know if this is suitable for the street. Perhaps on a twisty it might be appropriate.
I have a Stealth, so it's very similar to what you tested; LR AWD everything but for the motors and software (Performance). I just took it through a canyon..the same canyon I rode so often on a sportbike....and I loved it. Holds the road fantastically well, even with the AWD trim. I could see throwing in some performance springs later, though I'd keep the 18" Aero wheels.
As for regen, you were getting used to this and this is just part of the EV experience. But, this is a great feature to get some miles back (especially going downhill) and you'll come to use your brakes rarely. You will save on brake discs too, with less brake dust generated.
I don't sense the build issues like others, but I've never owned any of the sport luxury brands. The Abarth was a doddle (and sounded great) but only costs $25k (or did then).