I recently added the Hella air horns to my car for the same reasons you mentioned. Now that I have gone through the effort of installing all the components and trying very hard to hide all the components, (2 horns, compressor, wiring) I would consider another option.
An easy alternate is to buy used horns from a junk yard (ie, horns from a Volvo or a Cadillac) that have deep sounds. You could pick these up for very cheap. Then wire them up to the existing horns (in the front of your car) and see if you like the sounds without removing the OEM horns. You can mix and match different sounds, or even add another sound to the 2 existing horns.
By replacing the OEM “beep beep” horns with air horns, I had a difficulty with the ‘third’ horn that is also used for the alarm. I didn’t want to disconnect it and loose my alarm horn. So now I have 2 air horns and one “beep beep” horn.
When I honk my horn, I hear both sounds (in actual fact, the “beep beep” sound kicks in first until the compressor builds enough pressure to sound the air horns). But the time lag between the two is very short and you wouldn’t really notice.
Good luck with your winter project.