Its a pretty decent color but it dependents on your personal satisfaction. 1D4 silver complements the chrome trimming in Corolla. I have a 1d4 silver myself, and the car is driven on the dusty patches on Islamabad expressway and PWD to Bahria on daily basis. I can say that the car doesnt look like it requires cleaning. Somehow the car looks a bit bigger with this color. A polish after two or three weeks really brings out the color and it stays that way.
Superwhite too is very decent. It all falls on your personal liking and disliking. Also, If you had read one recent article on how a white corolla is mistaken as a rental car, that too is concerning.
