ya 1 can go for study material and complete all 8 subjects in 3 months.How people come with such ideas and mislead other members.1 should be realistic.
I would like to recommend you to go with munish bhandari plus icai PM,
First complete your entire syllabus by sticking with manish bhandari main module.. It will take you almost 2 month if you do daily studies of 4-5 hr per hour then start solving PM question.