HERE YOU GO IF IT CRASHES YOUR GAME JUST COPY AND PAST OVER ORIGINAL FILES.

CONTENT.XML

<Item>
<parent>vehicles_dom_interior</parent>
<Item>
<filename>dlc_ccrv69:/data/vehicles.meta</filename>
<fileType>VEHICLE_METADATA_FILE</fileType>
<overlay value="false" />
<disabled value="true" />
<persistent value="false" />
</Item>
<Item>
<filename>dlc_ccrv69:/data/handling.meta</filename>
<fileType>HANDLING_FILE</fileType>
<locked value="true"/>
<disabled value="true"/>
<persistent value="true"/>
<overlay value="true"/>
</Item>
<Item>
<filename>dlc_ccrv69:/data/carcols.meta</filename>
<fileType>CARCOLS_FILE</fileType>
<overlay value="false" />
<disabled value="true" />
<persistent value="false" />
</Item>
<Item>
<filename>dlc_ccrv69:/data/carvariations.meta</filename>
<fileType>VEHICLE_VARIATION_FILE</fileType>
<overlay value="false" />
<disabled value="true" />
<persistent value="false" />
</Item>
<Item>
<filename>dlc_ccrv69:/data/dlctext.meta</filename>
<fileType>TEXTFILE_METAFILE</fileType>
<overlay value="false" />
<disabled value="true" />
<persistent value="false" />
</Item>
<Item>
<filename>dlc_ccrv69:/%PLATFORM%/vehicles.rpf</filename>
<fileType>RPF_FILE</fileType>
<overlay value="false" />
<disabled value="true" />
<persistent value="true" />
</Item>
<Item>
<filename>dlc_ccrv69:/%PLATFORM%/vehiclemods/voiture_mods.rpf</filename>
<fileType>RPF_FILE</fileType>
<overlay value="false" />
<disabled value="true" />
<persistent value="true" />
</Item>
</dataFiles>
<contentChangeSets>
<Item>
<changeSetName>ccrv69_AUTOGEN</changeSetName>
<filesToDisable />
<filesToEnable>
<Item>dlc_ccrv69:/data/handling.meta</Item>
<Item>dlc_ccrv69:/data/vehicles.meta</Item>
<Item>dlc_ccrv69:/data/carcols.meta</Item>
<Item>dlc_ccrv69:/data/carvariations.meta</Item>
<Item>dlc_ccrv69:/data/dlctext.meta</Item>
<Item>dlc_ccrv69:/%PLATFORM%/vehicles.rpf</Item>
<Item>dlc_ccrv69:/%PLATFORM%/vehiclemods/voiture_mods.rpf</Item>
</filesToEnable>
<txdToLoad />
<txdToUnload />
<residentResources />
<unregisterResources />
</Item>

VEHICLE META

<Item>
<parent>vehicles_dom_interior</parent>
<child>ccrv69</child>
</Item>

@ArteX Just tried the stuff I mentioned above, and it works perfectly fine. Took a screenie before parking it: https://i.imgur.com/lr683v5.png

I'll try to list the things I did, in case I broke something:

1) In content.xml (ccrv69 > dlc.rpf > content.xml), I added under <dataFiles> the following entry:

<Item>
<filename>dlc_ccrv69:/data/handling.meta</filename>
<fileType>HANDLING_FILE</fileType>
<locked value="true"/>
<disabled value="true"/>
<persistent value="true"/>
<overlay value="true"/>
</Item>

2) And under <filesToEnable> the following entry:

<Item>dlc_ccrv69:/data/handling.meta</Item>

3) Then I removed the vehiclemods file entries under both, <dataFiles> and <filesToEnable>, as the vehicle uses no custom tuning. (And, as stated in my previous post, the first entry for it was also invalid. It had nom_mods.rpf instead of voiture_mods.rpf, as the second entry.)

4) I placed a handling.meta file from another Camaro inside the data folder and edited it a little. ( Used Impactjunky's "4 speed" preset: https://www.gta5-mods.com/vehicles/semi-realistic-handling-and-top-speed-for-neophyte-s-69-camaro-impactjunky ), but any should work.

5) In handling.meta (ccrv69 > dlc.rpf > data > handling.meta), I changed <handlingName> from CAMARO_SS to ccrv69.

6) In vehicles.meta (ccrv69 > dlc.rpf > data > vehicles.meta), I changed <handlingId> from DUKES to ccrv69.

7) In carcols.meta (ccrv69 > dlc.rpf > data > carcols.meta), I changed the <kitName> to 0_default_modkit (since the car uses no custom modkit) and the ID Value beneath it to 0. I also changed the ID Value under <Lights> from 900 to 0, and I removed the <name>VOITURE</name> entry you had at the bottom of the file, which seemed to be of no use.

8) In carvariations.meta (ccrv69 > dlc.rpf > data > carvariations.meta) I changed the lightSettings value to 0 (Though all the light settings are irrelevant, I just wanted the default light settings. You can ignore these minor changes; I'm just listing them to be sure.

9) I deleted the vehiclemods folder along with the empty .rpf file inside it from ccrv69 > dlc.rpf > x64 since they're unused, but you may want to keep them (along with the vehiclemods entries in content.xml) for adding tuning parts in the future.

I think that's all. Hope I didn't confuse you too much. I can upload/send you the .xml and .meta files, if it's of any use.

Thanks again for a great mod!

@keirona Ah, yes! I said it in my first reply and forgot in my second, dang. Thanks for pointing it out!
It's basically the <child> at the bottom changed from "voiture" to "ccrv69" in the vehicles.meta, like you said.
And I forgot I defragmented the .rpf too with OpenIV for the excess size, welp. I rushed my reply earlier.

@ArteX Glad to be of use! I just typed a somewhat long reply, I didn't really do much work there tbh; it's 5 mins of work tops. All the credit's yours.
I'll happily upload and send the mod right away!

Oh and the one who should get credit is probably @Impactjunky for his handling settings file. (I can make my own if necessary, but his one is quite nice/realistic, I'd keep it. He did a great job on it.)

Also, as @keirona stated above (thanks!), I forgot to mention a couple of changes. The dials model name in the vehicles.meta and and the .rpf's defragmentation for the size fix.

Lastly, I didn't compress the mod folder since I don't know what program you prefer (I hear WinZip and 7zip are the best for compression). Uploading the folder as it is to MEGA and sending the link in a PM shortly.

P.S. I hope you're familiar with the Light Settings ID stuff that I changed, which affect things like the car's lights.
These IDs each have like different corona color, placement, intensity and such. It's like each car has its own ones in the game and you can choose any. I'm using the default one as I don't use any coronas (Using "Corona Begone" and some other mods) and want all of my car lights to be white and such. They look much more realistic that way, but I understand some people would perhaps want an older car like this to have more "yellow-ish" lights.