I recently got a Farbin horn.
Came with a pack of two horns.
Mounted one and tis LOUD as heck.
Impressive sound and by far the loudest I have heard.
IMO horns are pointless on a motorcycle, they do NOTHING for you other than expressing yourself AFTER you avoided something. Loud pipes save lives is BS as well. all it does is be loud AFTER you pass someone or piss of the dog that is chaceing you (happened to me) Get good at riding and practice panic stopping and object avoidance.
I put train horns on my POS car for a reason, to be ANOYING and helarious. IMO a rocket does NOT need a good horn or IMO any horn at all.
BUT if you must upgrade it (free country and all that jazz) the best electronic horn i have had in quality and longevity was PIAA and WOLO, but IMO they have the same flaws of all of these. CHEAP CHINESIUM
Im not a guru but i have done a TON of stuff like this and BY FAR again the 955 / VW torege horns are the best. they are TINY, cheap and CRAZY loud and LOW amp draw. why? GERMANS
all you need is
Wiring Harness 7L5971073 $40
High Tone Low Tone Horns 95563502101 and 95563502201 Used $60
a 4 post relay and some solder and shrink wrap .
I have tested every single thing that makes noise and moves with a very high end DB meter i have. these things BLOW SOME SERIOUS SOUND. You could eaisly fit them one on each side under the covers under the seats.
I actually wanted to do this myself but again... too much time, not enough train horns!