it is the GTA3 engine, there is no 2 ways about it. half of you seem to think the engine consists of the models contained withing, IT IS NOT. The engine renders the objects, obviously they are going to be different, that is the whole idea of releasing a sequel.
Its like half life and gunman chronicles. Same game engine, different models textures and content. Quake 3 and Star Trek: Elite Force. Same engine, different shit.
You think the coders of GTA3 wrote a completely new graphics engine for GTA3:VC ? Think of what you are saying before you say it. It is the same engine with new models textures and a few extra shit. I have moved models and textures between games, im not giving you an opinion, im telling you the plain facts. The engines are one and the same.