Rockstar has added a page about some of the new vehicles you'll be finding in The Ballad of Gay Tony. They've also added 5 new screenshots of said vehicles.
Two of the cars parked at Bahama Mamas in the 3rd screenshot look new. The one behind the taxi looks like a convertible Infernus or something similar (from the front), and the car behind it looks new as well.
Ford GT and Dodge Charger SRT-8 I think. Thats from the top of my head so I'm not sure. Anyone want to confirm?