I just looked at the screenshots of Gran Turismo 5 on virtualir.net, the ones where the camera provides a distant landscape view, and I come to the conclusion that the detail in the game is solely a result of artists working the textures and being careful with the pallette. There really aren't that many polygons or special texture tricks from what I can see. This is a much different impression than one gets when watching the GT5 videos. Which should give all of us track makers some hope in achieving professional quality! Concentrate on the textures more than adding polygons, make use of DX9 features, let the game's shader do it's thing, etc. Even the GT5 cars seem to be oriented towards textures rather than polygons.