So with a 255/35-20 being 27" tall, which is ~2% deviation from OEM, I'm reading about possible stability control issues[?]
255/35 = ~27.0"
235/35 = ~26.5"
~2%
Are you going to set your wheel/tire config for the "Performance" option
If the car calibrates based on the selected wheel/tire, which I assume, then that would be (based on that package having a 245/35):
255/35 = ~27.0"
245/35 = ~26.75"
~1%
... or do people just bolt on wheels and say to hell with it, I'm sure it'll work
(I've certainly done that a few times, but I'm new to Tesla)