Depends what your going to use them for, if your using them for racing and have Brembo Superbike discs or equivalent 6mm thick discs then yes they are probably worth it.
If your going to be using them in anger and getting the most from them with thinner disc and end up warping the discs then probably not.
And for road use the answer to your question is No
Yep thanks Phil. Kev I was thinking of the using them in the 996 next year.
When I rode the 1198 at Oulton it had (I think) PZ4 pads? I know the calipers are different to the 996 but the stopping pwoer was awesome. I know some use them in the 848.