Just like the writer of the above article I don't know the details, but from the sound of the press release it seems that Fiat sues not for a negative opinion about MiTo expressed by the magazine, but for something like (I don't know what's an appropriate english legal term) "intentional misguiding of consumers". If a car is slower than its competitors, it doesn't mean it's "technically inferior" only that it's slower. Therefore such a statement without thorough assessment of technical aspects of a car is misguiding and unfair. However, I guess it's a matter for a consumer ombudsman (don't know if there's such an institution in Italy), not for courts.