Yes, despite being mostly live-action the trailer is an obvious tease: weather, night racing, Rally, Top Gear, and possibly open wheel. Weather and night racing was supposedely going to be in Forza 3, but was cut do to time constraints. They had concepts for it, as you can see at the bottom. Also, don't forget Microsoft owns everything PGR and that includes the tech, so Turn 10 will likely make use of the weather effects tech from PGR4 in some form.
