WARNING!!!!!!    DON'T FORGET TO BACKUP ALL FILES YOU ARE ABOUT TO CHANGE/REPLACE!!!!!!!




Open "vehicles.img" with Spark IV      "...\Rockstar Games\Grand Theft auto IV\pc\models\cdimages\vehicles.img"     

search "fbi.wtd" and replace the existing file with the new "fbi.wtd" 
press "save", play the game, have fun