ISCA

Only PM is sufficient if you are looking for just 40. But you need to understand PLUS remember, what you study. Also try to attend one day crash course from Amit Tated or Swapnil Patni just before the exams. The way of teaching the whole book point by point without even looking in book is great. It gives us so much confidence that if they can do so, then why cant we, we can learn atleast 40% of the course. 

Don't take ISCA as hard subject, just keep on daring it and it will give up. All the best.

PM wouldn't be sufficient. You should refer the book of CA Sudeep Mangla "Secret to crack ISCA".

It is one of the best book for self study. It consist of full Coverage of the ICAI study material, Wide range of diagrams & Charts. Lengthy topics have been very well summarised and Simplified explanation to headings. This book will surely help u to prepare for ur exam. 
 

If you have not been able to complete the Study Mat then switch to Manish Valecha ISCA textbok. Dont waste your time in SM and other textbooks. Manish Valechha textbook is mnemonic based and it is the largest selling textbook of ISCA. 

See the Attachment -- How to prepare ISCA by CA Final AIR 1st Rank Holder