make sure you have ingame graphic settings the car textures set on HIGH !
make sure you have in the mod all the textures saying Hi_....
make sure your f1graphic.cfg file, the first line must be on 1 ! and have a look at the other lines i mentionned below
1 ; f1graphics.cfg controls all settings (default 0)
0 ; Texture quality : 0 => max 2 => half 4 => qtr 8 => eigth
1 ; Increase car texture quality (1 on, 0 off)
1 ; Full 32bit textures