Allow me to step in here, given that I worked on the marketing side of several NFS games (SHIFT, NITRO, HP, World, SHIFT 2 UNLEASHED, The Run) before leaving a few months back. We always had a great relationship with Porsche going all the way back to Porsche Unleashed on PS1.
Turn10 are a bunch of hypocrites. EA had to pay through the nose to get Ferraris for one DLC pack for SHIFT1 - only on 360 because we couldn't get licenses for PS3 from anyone. This is gamesmanship in the software industry and happens all the time. EA has the license and if Turn10 wants it, they're going to have to pay up. They chose not to, so TS - or more accurately, RUF - for them.