Daf Cf for GTA4
Backup your \GTAIV\pc\models\cdimages vehicles.img file. This mod is Beta so it may cause your game to crash so very important backup your files.
Unpack the archive with WinRAR
Run SparkIV and open vehicles.img located in:GTAIV\pc\models\cdimages\
Click Import and select packer.wft
Click Rebuild and Save.