I say, and with God's success: There is no specific requirement for the Witr prayer or any other prayers, and it is permissible to recite whatever you wish from the Quran in them. However, it has been reported from Abu ibn Ka'b, may Allah be pleased with him: "Indeed, the Messenger of Allah, peace be upon him, used to recite in the first rak'ah {Glorify the name of your Lord, the Most High} [Al-A'la: 1], in the second {Say, O disbelievers} [Al-Kafirun: 1], and in the third: {Say, He is Allah, One} [Al-Ikhlas: 1], and he would make the qunut before bowing" in Sunan al-Nasa'i al-Kubra 1: 448, the Selected Hadiths 3: 420, and Sunan al-Daraqutni 2: 31.