Resizing In Unity Does It Hurt?

I read that it is best to make sure the size of your objects are fairly exact in your modeling program before import into Unity. Does it really effect the engine if you resize objects in Unity?

Changing the import factor doesn't change the performance, but from my understanding scaling an object frequently by script will hurt your performance. See links below.

Forum Post see ReJ's post at the bottom of the first page.

Yet another forum post

Scaling an object can have an impact in several regards. Matthew Wegner, in one of the Unite presentations he's given (the video is on Unity's website), mentions that PhysX is less optimal when an object is scaled in engine (not with import settings), especially when instantiating an object.