RT & GS owners - which stebel horn did you choose?

I see that there are four horns available from Stebel, http://www.stebel.it/stebel2012/products.asp?menu=products

I have an 08 R1200RT and am looking to add one.

To give me, and others advice, I thought it would be good to get some general responses which include the following.

Let us know (via the poll) which one you chose.

Then in a reply to the post, add anything you like or dislike about it, what you had to add as an extra in order to install the horn and have it work (i.e.: fuzeblock, new switch)

Did you keep your original horn too?
How difficult was it to mount? (did you have a good source for any mounts required?)

Thanks for sharing.

I have the Nautilus on my '07 R1200S. This was done after the Magnum ('twas not loud enough). The Nautilus is loud enough.

Toot when needed, sit on when a tractor-trailer truck tries to cut you off. I've done both, successfully.