Roma supporter living and working in England here, you shouldn't fear visiting Rome because of incidents of the past here are main ways to avoid falling victim of the Ultras.
The night before the game is when most attacks happen to supporters visiting Rome stay away from congregating with fellow supporters who arrived early in Irish and British bars, the Ultras send spotters to Irish and British bars looking for big groups to fight with when they play British clubs.
If you want to go and have some drinks have them in the hotel bar or in a resturant, if you do go to a bar don't hang your flags outside as you are just telling them you are there.
Other than that it's just the same as every big away game you will have in England, my biggest advice to you as someone who experiences both matches in Italy and England every year you won't get away with talking to police and security in Rome like you do in England so watch out for them, they love nothing more than showing football fans who is in charge and the ones in Rome are one of the worst of Italy.
A lot of this will depend on the situation of the group, if Roma is eliminated the stadium will have many empty seats and the fans will be quiet but if Roma can qualify this will be one of the most hostile atmospheres you will experience.
Stay safe and enjoy your loss, Forza Roma!