About the starting grid: I wanted to use textures too, but there's a bug on my track, I think it's becouse of the pit entrace, but I can't map the textures correctly from the third row and the row that come behind.
About the Central Building: I have a clue about the problem with those buildings. When you use 50's/60's carshapes, the drivers head uses to desappear when you look the car from behind. I think it happens becouse with the original carshape the head is covered when looking from behind. So, desabling the head was a way to maximize the game speed.
I think the sabe happens to the objects. In the original tracks they were not intented to be seem from certain angles and positions, so they are set to be turned off sometimes. I couldn't figure out how it happens with the Jerez Tower, the only thing I could imagine is that there's a moment when only the top is visible from car view, and AAS used only the top poligons to make the building, what makes me think the bottom poligons were turned off.
But it's a diferent angle compared to the "desappearing effect" on my building, so I'm not sure...but I really think this kind of problem has something to do with this.
It would be nice it the trigger for this effect were in the object definition and we could find it.
I hope you understand what I mean becouse my english is very limited
Regards!