If my memory serves, there is a thread on here and the installation involved a separate feed through a relay. Standard wiring is unlikely to be suited to the increased current. Andy
The horn is in the beak and just the lower panel needs to come off (IIRC 2 screws). I fitted the Mini Denali on mine, and it was a straight swap and better than the OEM Italian squeaker. Not a lot of room under there but just enough.
You need the relay wired in & also requires the extremely expensive bracket thingie for going on engine guards. Well worth it though, post a picture of mine tomorrow.