Where to install:
update > x64 > dlcpacks > patchday3ng > dlc.rpf > x64 > levels > gta5 > vehicles.rpf

= Step 1 =
Using OpenIV navigate to the location above listed above.
If required please copy this to your "mods" folder, OpenIV will warn you if this is required)

= Step 2 =
Select edit mode at the top and then import the 2 downloaded .yft files and the .ytd file into the vehicles.rpf