i think u shud atleast go 4 D.T classes once as u'll cum to about new ammendments and the strategy as to how u shud proceed with D.t..its my experience........
i have passed IInd group now in Nov.2007 attempt, and i am proud to tell you that i have not taken any classes in my life time so i will sugget you that if you go through direct taxes material and one text book of any author which is recommended by the Institute that is sufficient for you to get atleast 55 marks so go ahead