Self-studied exams don't look good if you skipped out on an opportunity to take the AP class. Besides, if you take them during senior year, they'll never appear on a college transcript. You're better off taking as many exams as you can do well on NOW, at the end of junior year, and have AP classes during senior year.
Also, do NOT report what you project that you will get. Colleges don't care; they want solid proof that you will do well in the class, and a numerical grade in a high school class is a better indicator than "I love Economics, so I'm projecting a 4 on the Macro exam." And if you report your projected scores in the "AP Exams" section, it looks like a desperate waste of space. Don't do it.