Stock vs. Hella
After having some bonehead back into my car, as I was stopped and leaning on the horn, I decided that I've had enough. I now have a bigass Hella truck horn! It's loud, but not overwhelming. It's not nearly as piercing as an air horn, but it certainly gets one's attention. I selected the 310Hz model and my Evo now sounds like a Mercedes tractor trailer.
We have two horns in our cars: one located behind the IC and the other under the front clip (driver's side). I replaced only one of the horns. Perhaps I'll replace the other, if I ever need to take the fascia off, but the single horn is plenty for now. BTW, the truck horn tips the scales at a little over 1.5lbs (!).
I'd like to credit the folks at Streettuned Motorsports who did a great job with the install.