INSTALLATION: Place the "vehiclemodelsets" file in "mods/update/update.rpf/common/data/ai"

If that file is modded, and want to have these cars in your modded file, you can copy the lines, only if you know what you're doing.

The modded lines are in "MUSCLE_CARS_MODDED", "MUSCLE_CARS_MODDED_2", and "LS_CUSTOMS_MODDED_SP".

Just simply copy those entire lines and replace the old ones, and make sure the lines match up with each other, otherwise you'll get an error.

For the vehicles.meta, place it here: "mods/update/update.rpf/common/data/levels/gta5"
 
Reason why it's needed since some of the cars default wheel types don't match up with the intended wheels picked for the modded cars. For example, the Dominator will spawn with big "Spooner" muscle wheels, instead of the "Mercie" wheels I chose, which are in the "Sport" category.

If you have a modded vehicles.meta file, just search up "Gauntlet", "Ruiner" or "Dominator" and scroll down until you find the "wheelType" section.

Then, just replace them with the default wheel type with these ones:

Dominator: "VWT_MUSCLE" to "VWT_SPORT"
Gauntlet: "VWT_MUSCLE" to "VWT_SPORT"
Ruiner: "VWT_MUSCLE" to "VWT_LOWRIDER"

After that, save and you should be set!
Just load in and go out looking for these rides.

I've made some screenshots showing where these modded cars will spawn, and what time as well.
Check the "Locations" folder to see more.

Anyways, after all is said and done, you got yourself some clean looking muscle cars that'll spawn around LS, enjoy!
-EcLiPsE-