First off - No you do NOT have to remove the bumper or grill to install these horns.
It took me 20 minutes to install the hellas with the bumper on. The 5 mins to take off and 5 mins to put the bumper back on would have slowed me down and been more of a hassle with risk of breaking plastic tabs.
What you need:
Hella Super tones http://www.subimods.com/hella-supertone-horn-kit.html
Subimods Hella Bracket http://www.subimods.com/subimods-com...s-bracket.html
Subimods Hella Harness http://www.subimods.com/subimods-hel...-kit-2041.html
Ratchet set, zip ties, wire cutters for the zip ties, WD40.
Step 1: Prepare the horns.
The hardest part of this install was removing the small bracket from the super tones. (See image below). To get that nut off I sprayed each nut with WD40 waited a bit and used a blanket to hold the horn snug and a ratchet to remove the nut.
Next, use that same nut and the screw built into the hellas to mount the horns to the Subimods Bracket. Then go ahead and install the 4 female power connectors on the Subimods harness to the horns.. copper terminal is positive/red. My set has no copper terminals so polarity doesn't matter seems to be the consensus.
It should now look like this:
Step 2: Remove one of the stock horns.
The stock horn behind the grill will block the subimods bracket, and since you need the connector from the stock horn to trigger the Hella relay it wont be on anyway... The other stock horn which is well hidden will remain on. Reach your arm up from under the bumper with a ratchet and undo the bold and remove the horn. Detach the wire running to the stock horn right at the horn. It is covered in conductive grease.. so have paper towels handy. The nut is attached to the metal plate and wont fall down.. just leave it there.
Yes, I am skinny but I had more than enough room to reach under.
Reach under there again with a ratchet and remove the bolt above the open hole which holds the hood latch. The nut is attached to the back of the plate.. it wont go anywhere.
Step 3: Mount the hella's.
Now... feed the whole prepared hellas/bracket/harness in and into place.. use that same screw you just removed to tighten it in place.. just let all the wiring hang for now.
In the picture below I had it upside down.. I had the more narrow part of the bracket towards the top.. I dont know if it matters.
Level them and tighten with a ratchet.
To be continued... about to hit picture limit.