If the reason for testing to API 1104 is because the code book is smaller than D1.1, re-think your logic. But if it is the code that deals with what your familiar with, just buy the 1104 code book and study the hell out of the appendixes! Yes the book is smaller but the appendixes were killer and when i took the test last july the last 15 ?'s were all directed to the appendixes content. If you understand them, they rest will be a breeze. As far as the listing above :aws api 1104 20th ed., that is the code book and not the study guide. When i walked out of the api code test i talked to engineers that said the math required on the test was extremely tough. But the thing with the math is that the test ?'s were also the sample ?'s in the code book! These guys were spending 4-5 minutes on the ?'s when the answers were right in front of them. That's the type of curves thrown at you in the testing. And you need to remember that the api test is 60 ?'s in 2 hours vs. the D1.1 test with 45?'s in 2 hours. And the kicker is that no matter what code you test in, u pass and your a cwi reguardless the code. Testing in api hold no more prestige than D1.1. Whatever your choose, best of luck.