The most of these "off road roads" are just gravel roads, some in good condition, some not (very big stones sometimes, or mud in case of rain). Most of them are open to normal traffic, so if you want to destroy your Porsche you are welcome ;-).
There have been a lot of Teneres and XTRs this year. But I would recommend a tyre like Heidenau K60 or something more offroad orientated like a TKC80 or Michelin T63 (was my choice this year).

DMI: I think he means the FMI, this is an Italian motorsport association. You need to become a member their, this can be booked together with the entry fee

Cheers
Solitario