Best books for self study

Paper 7- Girish Ahuja

Paper8- Vandana Bangar

All the Best....

Paper 7- T N Manoharan or Vinod Gupta

Paper8 - Banger

For DT Vinod Gupta sir's Notes are excellent I have not gone them totally but they are really very good for clearing minor doubts. and You can also you Singhania Sir, book which is very good one for conceptual clarity with practice

For IDT there are many book every book has its own advantage 

I would like to prefer you Dippak  GUpta if you want straight forward approach for exam purpose.

But if you want to detailed study then go only for V S Datey and nothing else.

book of Bangar Sir is not bad its also good but I would not like to prefer you in comparison to above books

Thanks

Paper 7- T N Manoharan (Concise) or Vinod Gupta (Detailed) (refer any book but do make your own notes for lengthy & technical portion)

Paper 8 - N S Govindan (Easy Approach - best for self study) plus Practice Past Exam Qs. from any book Banger or Padhuka