I think anyone with a brain can figure out that is NO WAY GT5 yet. I was impressed with the opening shots and the pit crew, and lots of cars, and that was it. Everything breathed GT4 all over it.
Come guys, it's been around 6 months since GT4's release and they were exhausted. They first released the VGT video for E3 because they needed to hype Sony's PS3 and build a fan base. They had no time. Now, they're just trying to show a few things and build a bigger fan base over the next 2 years.
No one has had time to recreate an entire track using a new dynamic lighting engine, new physics, etc. The amount of programming and texture work is insane. They're still experimenting with PS3 hardware. If you think about it, motion capturing pit crews is damn easy considering you don't need a PS3 to do it. The beginning renders on the video also are probably experimental shots with new lighting, and may have wanted to get a crowd reaction. I'm sure they're close to falling into a permanent path of what lighting and physics to use, but other than that...everything is still experimental.
We will most likely see some real, hardcore footage of EVERYTHING GT5 at next year's E3. No old GT4 cars, tracks, anything. All scratch, all new.