Of course, Napoli has performed well in their domestic league, but I'm not certain about how they can progress in the Champions League this season, as the competition will certainly be a tough one to get to the final.
Apparently, two teams will qualify from the group stage and I believe Napoli could stand a chance of qualifying from the group. Also, teams like Inter Milan and the likes are not performing well so far in their local League.
we all saw how they struggled against Udinese, with a horrible style of play, so I'm not sure Inter will be able to play better than last season in the champions League. It is really going to be a tough test for inter Milan in the group stage, having known that they will face big teams like Liverpool, Arsenal, Atletico, and Dortmund. Qualifying through these phase will only happen like a miracle!
Some teams were unlucky with their opponents, but I think that now for such teams to get out of the group should not be too difficult, although if you remember how PSG were on the verge of getting out in the last group tournament, now I understand that anything can happen. Napoli and Inter are good teams, but I do not expect either of them to win the Champions League, because there are stronger teams that can beat them. Serie A, although it has become more competitive, I think that the level of their championship is not high enough to compete on equal terms, although Inter managed to reach the final.