Same deal, if the car had them before, it’s mostly the same car. If it’s a modification, it’s a more different car.
What it comes down to, for me, is the difference between repairing/replacing and modifying. Keep doing the latter and you are definitely going to have a different car.
If it’s the same model of drivetrain, like a replacement one, I’d say yes.
what if i’m putting an electric one in to comply with new emissions laws and get a break on tolls
Partially different car then.
how about if i’m adding pop up headlights and t-tops through which to better express my personality (pop up headlights and t-tops are cool)
Same deal, if the car had them before, it’s mostly the same car. If it’s a modification, it’s a more different car.
What it comes down to, for me, is the difference between repairing/replacing and modifying. Keep doing the latter and you are definitely going to have a different car.
Pop ups and t-tops are very cool though.