I don't think there's a huge difference between the physics in this game and the physics in GT3. The big differences are in road texture (La Sarthe is insane!), wind resistance, and much more pronounced elevation changes. You get some insane speed going downhill Costa Di Amalfi, and in Fuji '05 the final turn is almost like the Laguna Seca corkscrew in reverse, and it's a total mofo. Oh and the sensation of speed is like eleventy billion times better than it has ever been in this series.