How many SAT subject tests should I take?

<p>I'm looking to go to some top tier colleges like Yale, Harvard, Northwestern, Stanford, and etc. I'm a sophomore and am taking 2 AP classes (Computer Science, European History). Next year I plan on taking AP Physics C, AP Calculus BC, AP US History. I plan on taking US History, Math Level 2, and Physics subject tests. I know only 2 are required, but does it look better if I am taking more than 3. Other classes I am taking next year Spanish 4 Honors (senior year AP Spanish Language), and a Regular English class.</p>