For controlling extras, use the "GTAIV SIMPLE NATIVE TRAINER" any version. 
If for some reason you can't select extras, change one line in the file "trainer.ini": 
VehicleComponents=1 - VehicleComponents=0


Extra1-front bumper's fog lights 
Extra2-mini spoiler
Extra3-standart grille
Extra4-
Extra5-front license plate
Extra6-modify grille
Extra7-some plastik
Extra8-front bumper' grille
Extra9-mega spoiler
