taking apart the steering wheel shouldn't be too difficult if you've got the tools...

typically there are small bolt covers on the left and right of the center portion with a large security torx bit , unscrewing that will let you remove the air bag, at that point you should be able to easily access the horn crap.

at least that's how ever other steering wheel I've ever taken apart has looked.


as for "supertones" it's a model of horn made by Hella... you might have better luck searching for "Hella Supertones"

they're really popular with the Subaru crowd, they're big and red and for some reason Impreza owners love to stick them in the grill...

check this out:
http://www.youtube.com/watch?v=j7VH-6158RI

I actually have a set, uninstalled, don't let the video fool you they are LOUD!

They're pretty cheap too. I, picked mine up new for $45 a few years back, they might not look bad centered behind the tusks on a VX