I've replaced the clockspring on my SVT. The symptom for me was that the cruise control wasn't working. Sure enough, when I tried the horn, that was out too. If both are on the fritz, then yes, you will need to replace the clockspring. As mentioned, you are going to want to disconnect the battery for at least 10 minutes - don't want to accidentally discharge the airbags ya know.
I seem to recall that yes, it was a PITA to do the work. Had to take off the black dash piece above the steering wheel (you know, the piece that contains the coinholder/vents). Also, if you do wind up replacing the clockspring, I know you need to be careful about how you have the wheel turned. I think you want to have it centered for when you put the new one on, but I can't remember exactly. Oh, and I think the airbag light might be flashing if it's the clockspring - just another possible way to diagnose...