LOUD horn wanted

I currently have a 2013 Toyota Sienna and a 2014 Toyota Taco. I would like a LOUD horn for both. I will keep the stock horn for normal "meep-meep" greetings, but I would like something that screams at stupid drivers. An alternate button will be needed for activating the loud horn.
I think something 145 db or louder will be effective. Any experts out there?

 

Air?

 

Sub'd for info i'd prefer to replace stock and not add wiring but always open to options.

 

I just came across one of these...claims 139db

http://www.amazon.com/Stebel-Nautilus-Universal-Motorcycles-Scooters/dp/B00CMX20H4

Anybody ever tried one? It's no train horn but for most of us it would get the job done. I found a few videos on motorcycles but no reviews on adding to vehicles.

 

I had air horns on a couple of F150s. You can just tap horn button and they are not loud.

 

Wolo has a train horn that won't break the bank;
http://wolo-mfg.com/