Answer
(Fatwa: 1891/1767=D/1429)
Performing salah with calmness and peace means that every part is performed with calmness with no haste. One should not hurry up to recite the Holy Quran and tasbihat i.e. he should pronounce them with fully with calmness so that the Quran and tasbihat are recited well. Therefore, the Ulama who have advised you to perform salah with calmness and peace are right, you should do so. Whatever you recite it should be with calmness.
The second matter is regarding shortening qirah at the time of needs, for example reciting short surah, three tasbihat instead of five times, or reciting only At-tahiyat or durood and leaving dua-e-masoorah due to tiredness of people as it can be done in tarawih when needed. So, whatever you recite in tarawih that should be with calmness. You should recite complete At-tahiyat and later durood, there is no wrong if dua-e-masoorah is missed. If you will recite all these in hurry, you may not recite them with calmness. However, it is better for Imam too to recite complete At-tahiyat, durood and dua-e-masoora calmly, but if he leaves dua-e-masoora it is also allowable. (شامى 1:523)
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband