Hello,
This is a thorough tutorial on installing add-ons with vehicle mods, etc.
[IMPORTANT INFORMATION]
Before installing add-ons, you need to make sure the .YFT files are below 16MB. If the .YTD file is oversized, you can lower the resolution/quality below 16MB so the texturing will not be glitchy, and will be formatted on the vehicle correctly.
Make sure you put the vehicles+vehicle modifications in a stream folder, you can organize the vehicles, and the mods through seperate folders.
Make sure to put the meta’s in the same directory as the resource.lua. You can recode it where it will read it in a different folder if you wish.
I took this Nissan GTR 2017: https://www.gta5-mods.com/vehicles/nissan-skyline-gt-r-17-add-on-replace as an example. It had an oversized texture, so I lowered the quality so the texture would be formatted correctly, and the car would look nice. You need a photoshop program, if you do not have one, download Paint.net
[Tutorial]
The __resource.lua will need some coding to read the meta files. It is optional to have a vehicle_names.lua to create the vehicle hashes for example:
vehicle_names.lua
Citizen.CreateThread(function()
-- Nissan GTR
AddTextEntry('0x9F05F101', 'gtr17')
-- Range Rover
AddTextEntry('0x9F05F109', 'rsvr16')
end)
In the resource file you will need the following:
__resource.lua:
resource_manifest_version '77731fab-63ca-442c-a67b-abc70f28dfa5'
files {
'vehicles.meta',
'carvariations.meta',
'carcols.meta',
'handling.meta',
'vehiclelayouts.meta', -- Not Required
}
data_file 'HANDLING_FILE' 'handling.meta'
data_file 'VEHICLE_METADATA_FILE' 'vehicles.meta'
data_file 'CARCOLS_FILE' 'carcols.meta'
data_file 'VEHICLE_VARIATION_FILE' 'carvariations.meta'
data_file 'VEHICLE_LAYOUTS_FILE' 'vehiclelayouts.meta' -- Not Required
client_script {
'vehicle_names.lua' -- Not Required
}
If you want the vehicle modifications, do the following:
carcols.meta:
<Item>
<kitName>1967_gtr17_modkit</kitName>
<id value="1967"/>
<kitType>MKT_SPORT</kitType>
<visibleMods>
you would want to change the mod kit value “1967” to “1008” - “1024” those are the only values for me that worked, if any other values work, please let me know
carvariations.meta
<kits>
<Item>1967_gtr17_modkit</Item>
</kits>
The value you changed the mod kit to in the carcols.meta is the same value you want in the carvariations.meta
Example:
carcols.meta
<Item>
<kitName>1008_gtr17_modkit</kitName>
<id value="1008"/>
<kitType>MKT_SPORT</kitType>
<visibleMods>
carvariations.meta
<kits>
<Item>1008_gtr17_modkit</Item>
</kits>
I do believe I covered most of add-ons, if there are any parts you are confused about, do not hesitate to message me 
