As for Sujud al-Sahu in this case, you are not required to do such Sujud if you intentionally leave the additional portion. And, according to some scholars, it is needed to do Sujud al-Sahu if you ...

Discover the ruling on reciting AlFaatihah behind an Imam during prayer. Sheikh Nasiruddin alAlbani argues that AlFaatihah should not be recited in loud prayers but must be recited in silent ones.