Importance and Status of Spirituality in Islam that has always Existed

Where does Spirituality (Ihsan/Tasawwuf/Sufism) fit into Islam which has always been there as opposed to the restricted and wrongly interpreted form of Islam that have sprung up specially in the last century? The highest level of Islam that contains all lower levels within it is "Ihsan" or "to worship God as you see Him". An exposition of "Ihsan" and where it fits into Islam.
http://www.masud.co.uk/ISLAM/nuh/sufitlk.htm