if i go 5lbs or more gross weight per corner (tire and wheel combined) i can definitely feel the car is heavier to steer and to brake.
i went back and forth between my current weds with DW's (5.5lbs lighter per corner) vs the stock 19's with RE050A's to compare and there is significant difference.
but for most folks driving as dd and stuff, no issue.
there is about 8lbs difference between my stock G's wheel/tire combo vs my summer 3pc wheel combo. the car definitely feels heavier to steer and brake.