PLEASE DO NOT REUPLOAD THIS WITH MY PERMISSION: 

Installation Method 1: 
Download a Software like TXDWorkshop (you have to edit an .txd file)
Then go (inside the Software) to: Your GTA SA Installation Directory>models>generic>vehicle.txd
Then repleace the originals with the downloaded Files (ONLY THE .PNG FILES)
THE .TXD FILE IS FOR THE FOLLOWING METHOD. 

Installation Method 2:
Repleace the whole vehicle.txd in Your GTA SA Installation Directory>models>generic. (WITH WINDOWS EXPLORER)

Thanks for downloading