At least in Ferrari's case, the car is wrapped, and according to this article, the Miami wrap uses special material that is lighter and better for the environment.
I would assume most cars are wrapped these days? I'm not sure.
(I'll reserve judgement on whether this Ferrari 'Miami' livery is doing this car any favors, looks-wise.)
http://www.planetf1.com/news/scuderia-ferrari-unveil-unique-blue-accented-livery-for-miami-grand-prix
