I was at Napoli away. The flares, fire works and generally 'unruly' attitude all added to the atmosphere. The fact I could smoke watching the game was great as well.
The Health and Safety regulations have led to our grounds becoming sanitised in England. I believe there is an understanding in Naples that the police control outside the stadium, but inside the stadium it is run by the Ultra's. Thats never going to happen over here. We've got people being lifted out for standing up ffs.
I was at Poznan and Aris away as well, but Napoli was a better atmosphere. By far a better atmosphere actually. The most impressive thing was at the end of the match, as soon as the final whsitle went they started playing this song. Everyone to a man in the stadium was still in the ground and singing it, and about 30-40 flares went up in the stadium. Although we had just been beaten, I was in awe of what I was witnessing.
Now as I say, the flare aspect is a no-go in England, but is it too much to expect everyone to stay to the end of the game and sing bluemoon? Half the stadium has fucked off at the final whistle whether we've won lost or drawn.
To answer the OP, there is nothing specific to take from the San Paolo, such as 'The Poznan'. Maybe we could adapt a better attitude towards supporting City? I just don't think its in our make-up to be the way the Napoli fans are though.