With regards to wheels, I always keep load rating in mind.
A Performance 3 has a Gross Rating of 4,806 lbs.
A Performance Y has a Gross Rating of 5,291 lbs.
~485lbs of difference
Just because you have a wheel with the same bolt pattern and correct outer diameter tire, doesn't mean the wheel will hold the load of the vehicle. It may hold a day, a week, a month, but from a long term sustainable daily driving perspective...
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I'm no engineering expert, but there's a reason why Tesla chose a 9.5" width with a +45 offset on the Y. Deviating too far from those specs....who knows the outcome...???
In theory, you could install a 255/45-19 tire with the proper load, speed specs (104W XL), the inside of a 19" Model 3 sport wheel will sit 18mm away from the suspension and the outside of the wheel would sit 8mm away from the respective fender, so the positioning/track is off (even though the tire is the same).
I would think this wheel / tire setup is going to yield some questionable driving/handling results. Any suspension engineering professionals here?