Will do this tomorrow. Got the hang of making sirens for GTA IV, so should be pretty easy for me to do.
I take it you want 2 IVAUDs, where one has Pier on the police car's third tone and Hilo on the ambulance's third tone, and switched around for the other one?
(ELS V7 has all 4 tones working in one car, if interested)
It turned out to be a bit more tricky for some weird reason, so i'm just waiting for a reply from a guy in the GTA modding scene, who's helped me with these things before.
Sound files seemed to be corrupt somehow (refused to convert to the format needed for gta) so i had to grab my LFS ones and redo them for GTA IV. Turned out nicely in the end.