So, the other day I had my wheel trims knicked off my fiesta from outside my house, this has inspired me to invest in some alloy wheels, seen a few that I like the look of but I don't know whether to get 15" like what I've already got or go up to 16" and if I do so will the increase in size have any effect on the car (like catching the wheel arch with the tyre etc)

Also, do I go for black alloys on a black car or do I go for the white ones?