I may just be lost, but is there a key that changes the siren to the next tone without holding down E? I see in videos of people changing the tone while in a pursuit and that would be quiet difficult if you had to hold down key E.

With LSPDFR; you can press "J" to toggle mute on the siren. Holding "E" ("G" in my case as I remapped it) will prompt a different siren, correct. 

Yes but i was wondering if there was a key to select the different tone. Instead of having to hold E for that. Like switching from a yelp to a whale. 

Not at the moment.