I'm pretty sure Gta 3, Vice City, San Andreas and all the others upto IV used the same game engine for physics and graphics. It just got tweaked as the years went by and the technology advanced.
I'm excited about V. Even without viewing the trailer, I can confidently say I will buy this. Rockstar have always made games that I enjoy.
Rockstar still has licensing rights to the Euphoria engine until 2018, so that will most likely be uses, which is fine as its a great engine. As long as there is no more low gravity, or cars with uber soft suspension...