I would like to replace the stock horn with a pair of Stebel Electric Horns. Can I use the stock wiring and steering wheel button. Do I need to increase the size of fuse, do I need to run the hot wire to the battery. Anything else I need to know.

 

You might want to call the manufacturer of these horns to ask those questions

 

No you need not to run the hot wire to the battery. but then we need to check what type of horn is this. why don't you contact the technician who is aware of such horns.

 

Compare the amp rating for the horn you want to the fuse size of your O.E.M.
horn.
If the new one is equal or less amps then the old horn, then you can definitely utilize the current wiring and steering wheel button.

Worse case is that the new one will have to utilize a $4 relay to power the horn from the battery. Triggered via the old wiring.