Well, i did mine over 6 years back. Not sure if things have changed by now. All i can say about this certification is its not a cakewalk. Most important thing is to stay focussed for the entire duration of 8 hours ! Although each paper is 1hr 45 min with 15 min break between 2 however you have to appear for all 4 papers in same sitting ! On guidance for study, the 2 books they recommend is more than enough and you dont need to explore anything beyond that.. I am not sure the rules are still same, i.e., if you fail in one paper you got to redo all 4 again ! Thats not enough, you must score min. 75% in each paper to clear this certification. You also have to write a technical paper within their specs and that too needs to cleared by AACEi before you can lay your hands on CERTIFICATE.
Hope the above help, however if you need any further guidance, feel free.