Installation:

1.Copy "2011mazda2" folder to :\Grand Theft Auto V\mods\update\x64\dlcpacks

2. Using OpenIV, go to: \Grand Theft Auto V\\mods\update\update.rpf\common\data — find the "dlclist.xml" 
and add the following line: 

		<Item>dlcpacks:\2011mazda2\</Item

3. (optional - it was not necessary for me )  Using OpenIV, go to: \Grand Theft Auto V\\mods\update\update.rpf\common\data — find the "extratitleupdatedata.meta" 
and add the following line:

		<Item type="SExtraTitleUpdateMount">
		    <deviceName>dlc_2011mazda2:/</deviceName>
	                      <path>update:/dlc_patch/2011mazda2/</path>
		</Item>


Done!

To spawn the car using the trainer type: 
2011mazda2