Karin
The Asterope GZ is a Karin sedan returning from earlier GTA games. Rockstar first showed it in an official screenshot (Grassrivers 02).
Image: Rockstar Games'55 Stanier
First shown: Rockstar media: Vintage Vice City Pack
Emperor
First shown: Trailer 2 + various Official Screenshots
Intruder
First shown: Trailer 1 (0:46, 1:03 and 1:07)
PMP 700
First shown: Trailer 1 (0:28, 0:30)