It doesn't work anymore with the latest update.
(14:48:16) | Failed to call hook 'AttachCarSirens' on plugin 'Sirens v1.1.1' (NullReferenceException: Object reference not set to an instance of an object)
at Oxide.Plugins.Sirens+SirenController.get_EntityPrefabs () [0x00012] in <85a97f98ae304fe49e124bdefe082a98>:0
at Oxide.Plugins.Sirens.DetachCarSirens (ModularCar aCar) [0x00024] in <85a97f98ae304fe49e124bdefe082a98>:0
at Oxide.Plugins.Sirens.AttachCarSirens (ModularCar aCar, Oxide.Plugins.Sirens+Siren aSiren, BasePlayer aPlayer) [0x00000] in <85a97f98ae304fe49e124bdefe082a98>:0
at Oxide.Plugins.Sirens.AttachCarSirens (BasePlayer aPlayer, System.String aCommand, System.String[] someArgs) [0x00075] in <85a97f98ae304fe49e124bdefe082a98>:0
at Oxide.Plugins.Sirens.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x001c8] in <85a97f98ae304fe49e124bdefe082a98>:0
at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <3606d2af539c45e4b5c61658e6a8b307>:0
at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <c2afd8354b8b4f3ca451cf5a1aa111c3>:0
at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <c2afd8354b8b4f3ca451cf5a1aa111c3>:0