Just collected my other car (2 year-old car) from Toyota SC in Sec19, PJ for having a new door, a new rim and a new rear bumper. Paid RM5,099 for the 3 items, paint job and some body work.
Even though its just a new rear door, the paint job was the entire side including front and rear fender, and both doors to bring the color to a better match. Yet! I still notice a color differentiation on the new door (brighter color). My Toyota is Silver color.
So what color is your UDM Ms. Cheah? The problem with metallic paint is itself, is a mixture of lacquer and the metallic dust.. Firstly, aging lacquer will turn yellowish, secondly, different thickness of the metallic dust will result in different tone... sounds impossible to match le!! Unless the whole car is sand down to primer.. then u get identical layer of paint every where, so no color differentiation.
Good luck!