I thought about using props_vehicles too but there are more models than only cars. Some render ugly with colors like some trucks, so I changed it in mine
to directly ask for specific cars and trucks.
When I tried FindEntityByClassname(ent, "*")) instead of FindEntityByClassname(ent, "propy_dynamic")) etc. in my script, it didn't work anymore.
Is the asterisk working as wildcard? It does when used like this "FindEntityByClassname(ent, "prop*"))"
but not alone.
I put up your script too but no car changed (but my server is very modded so don't take this as an example).
The hook is the right approach though like I stated in the scripting forum.
Even though it only worked on first round, I replaced player_first_spawn with player_spawn now and made a bool after use that seems to do the trick now.