Having Trouble with Non-Els cars/packs

Hey everyone,

I know that this may be one of a thousand questions, however, I'm just at a complete loss and I have spent a LONG time browsing the forums, downloading/uninstalling packs, staring at OpenIv until my head was pounding, etc. All trying to understand the issue that I am having with the vehicles I'm trying to install. 

I've mastered the art of getting them to spawn into my garage, and some I have even got to work perfectly. Although, that's about a 3/10 success rate. My problem is that the lights usually don't work. Either at all or some blues will work while some reds won't. Or vice versa. 

This happens even with the packs. I have also literally pulled up a YouTube video and followed along step by step to try and install the CHP megapack. And only 1 of those cars worked right. 

Now, I am installing everything in PatchDay22 because that is where the video I watched did. And that's where they spawn in. But is that my problem? Do I need to use specific PatchDays based on the mods themselves? I thought with packs, all of that was automatic with the installer? 

I'm still new to modding in general, however, I've conquered the plugin side of things, but man, I am lost with these vehicles. Any help would be greatly appreciated!