I was watching this show on cool shops (or something like that) and they were showcasing the farrari plant. In the background was a huge banner of a masaratti. Then later on when they were showing the paint line, a four door was being moved around. Last I checked, ferrari didn't make a four door. So I guess what I'm asking is: Are ferraris and masarattis made by the same people?

Yes. the Quattroporte has a Ferrari derived V8, as the Coupe does also.