You also have to make sure your car is impeccably clean before applying it, everything will show through. My friend found that out the hard way on his 240. We are in the process of removing it.
People plasti-dip their cars to protect the paint if they track the car, hit the show circuit a lot and want to keep changing things up, or intend to sell the car later. There is a guy I know of (I don't personally know him, but a lot of the people I hang out with do) that has an FD RX7, some of you may have seen it. His name is Phil Sohn. The car is actually a dark blue I think, but he keeps the plasti-dip on it. It was a flat black and now it is gold. My friend (RL Photography) does a lot of Phil's photo work, so you could look him up on FB to see some pictures. Here is a link
for the Google Image Search.