Sayyed Mohammad Al-Musawi, Sayyed Mohammad al-Musawi is originally from Iraq and heads up the World Ahlul Bayt Islamic League in London. Other than being involved in various humanitarian projects, he frequently responds to... Answered 2 years ago

No, it is not permissible to add on Salah any thing which was not recited or done by the Prophet (SAWA).

Third and forth Rak'ats have either three times of Tasbeehaat (SUBHANALLAH WALHAMDULILLAH WALA ELAAHA ILLALLAH WALLAHU AKBAR) 3 times, or one time Sura Al-Hamd only.