Is necessary having the textures from the folder "Add 2 models"
in your vehicle.txd (models/generic). If you don't have these 
textures so the tunning parts don't work. (yes but with out textures)
(models on white). Please add these textures with out compression and use Magic TXD
for adding..

>>On the game the car can be tunning on Transfender<<
Or use any trainer for get the tunning parts 