so far… Mounted the 2 Horns like this but the Rear bumper would not fit so…
Got the horns mounted just right
you would never guess what I had to do to get these to fit. lol! I literally cut the whole bottom part of the rear bumper off and faced the other 2 bells more Downward, got it to sound just right and now the rear bumper re installed after all that work
Cleaned it with some De Greaser “All purpose Cleaner” what a long hot day. lol!
Dude, you’re insane! I love this setup. I was lazy, so I just put my horns under my spare tire and cut holes on the front, sides and bottom of the spare tire well and put screen over the holes. Seems to work great and was easy as hell.
great thing about this setup is it is stealth. I Was able to keep my Spare tire and trunk space, along with being able to fit my cleaning supplies and mop bucket from work into my trunk still, Kept that in mind the whole time too heck.
Great setup. I would be too worried about a rear end collision destroying the horns though 
^^^^ True, Specially with all the stupid tailgaters around here, the Alternative would have been to Cut a hole in my trunk and face the horns out of it and lose the spare tire space and the trunk space.
That’s what I did, and my spare tire is now tucked in the space next to my air tank and compressor so the left third of my trunk is now taken up. I drive a 1999 Toyota Camry so it’s pretty much identical to your car in terms of space and layout.
Nice work once again man.
Thanks 
Hey crazy man! That’s really cool, stupid question, have you tried them yet in that configuration, my concerns are that the two bells facing each other so close, will have air pressure against each other & muffle the sound waves?
I once had some stuff in the back of my Hilux truck with K3’s & they would not sound because there was a sleeping bag an inch or two from them, they just gushed air, it was proper weird!
But hey, I’m guessing you have given them a cheeky blast & they sound ok?
^^^ After many tests I finally got them to sound right I have the 2 bells facing eachother more “Downward” hence involve me cutting off the whole bottom of my rear bumper.
http://s152.photobucket.com/user/repeatman/media/Honduh%20Train%20horn.mp4.html
edit I am taking my car to the shop to repair an Idle Problem, I just hope they dont press the Horn lol!