Raziel here in Italy, we take for granted that tourists will have different styles. While that's not always true, people with "low elegance outfit" which are from other countries are almost excused.
"ah, he is from xxxx, they do not usually dress as fancy".
There was once a video where an American guy gave counsels on those visiting Italy, and I remember two of them.
"do not search food outside between 14.30-18.00, because all restaurants are closed. Same goes for many other places.
Do not fear to be overdressed, dress as much as you want. You will never be overdressed, wait to see how they usually dress.".
But I think that it applies more to people over 30. Plus, we do not really care much. We are not elitist jerks xD