Are your replacements in a custom DLC (like the "modding" DLC that OpenIV uses)?
A lot of folks seem to have issues with a darkened lightbar, windows, and light covers when doing this, which blocks the light sprites.
Seems you either need to replace them at their most recent patch locations or install them as add-ons to avoid conflicts with other existing metas. That's a very non-technical way of putting it, mind you. There's lots of discussions about the root cause of this issue spread across various forums, comment threads, reddit posts, etc.
I finally decided I was tired of endless reading and tinkering instead of actually playing. I've gone to all add-ons with my fleets. I have enough packs at this point that even cars that have no metas I can usually find something suitable to copy-paste and rename a few lines.
Another vote for R+B (but hey, work/life balance and all that, take care of you! :9).
Also maybe a modest bit of side skirt lighting? Don't get me wrong, I'm not a fan of "christmas trees" like some!
My LSPD and SAHP fleets are blue/blue, however and I have some of your pack in use with other liveries at the moment.
Went through quite a few packs until I came across this. Fantastic work, especially since my headcanon eliminates Blaine and has LSCSO patrolling all non-incorporated parts of the island (plus Davis, of course). I especially like using the reversed liveries for fire/ems for a unified "county emergency services" feel.
That said, and since you mention it in your description, consider me a strong (VERY strong) vote for seeing reversed liveries for at least some of the other vehicles. Specifically I would ask/hope/wish/beg for a reversed tahoe livery suitable for using when calling fire/ems first responders through ultimate backup.
I do also note that one of the tahoe liveries in this pack says "DAIL 911" instead of dial, though I do see that some of your latest car packs has eliminated this error.
All in all, smashing work and thanks for allowing me to keep my department looking consistent and professional!