Is wearing a "suit" (jacket and trousers), or limiting oneself to trousers and a shirt/undershirt, considered imitating non-Muslims?

The basic rule for clothing is permissibility, with exceptions for what the evidence indicates is forbidden or disliked, such as: silk for men, transparent or tight clothing that describes the 'awrah, clothing specific to disbelievers, and men's clothing specific to women and vice versa. Trousers and shirts are not exclusive to disbelievers, but it is preferable for a Muslim not to wear them in public places if the people of his country are not accustomed to them.