A few weeks back, I installed the Flosser Air Horn from Slingmods. I really like this addition to the Sling
1) cars can really hear you when you need to hit the horn
2) when kids are staring you down in disbelief and you hit the horn, the horn just adds to their experience
3) an unexpected benefit - when driving at dusk, it scares the crap out of the deer on the side of the road and sends them scaterring back into the woods
Functional, fun, and safety all in one - really great addition