should buy new study material(ca final) or Not ???

My attempt ca final(new course) is in nov 11. i have bought some reference books in the last month like

idt-bangar,

dt-vinod gupta,

law-munish bhandari,

isca-dinesh madan(covering additional new chapters), AS-MPV.

MAFA-An shridhar

Recently i came to know that institute has revised/modified/updated the study material.

1.

Is their any change in syllabus that is not covered in the reference books that i am studying from ?

2.

Should i buy the new study material for all/some subjects?