Run openIV
Press EDIT MODE in OpenIV
Go to GTA V/x64e.rpf/levels/gta5/vehicles.rpf
Drag & drop files from the rar file provided into vehicles.rpf
this is the first version of the LSPD vehicles, these are not based off of any particular vehicle/county, they are my own. 

version 0.1
"Launch" crown victoria

This is a custom skin based off of my imagination, 
and it turned out pretty great, im extremely happy with how it turned out.