It looks like they've re-arranged/re-named a lot of the prepaid data options:
Da PC Ricaricabile | TIM
They no longer have time-based options but the Senza Limiti plans have clear caps, 2, 5 and 10 GB levels. Do they throttle after those thresholds or cut you off?
Looks like they have some initial 4G (real LTE) plans but those plans are off the charts price-wise. Doesn't make sense for a visit but if you live there, you should be able to get by with 20 GB per month for both home and mobile use. Of course the coverage must be very limited.