The senior year report is important to show your commitment and strengths as a student. Do not make the mistake of taking all easy courses or avoiding a math, science, or language if you hope to attend a selective college. Senior grades are very important, some colleges have withdrawn acceptances after receiving poor spring grades. College admissions officers vary widely in the importance they attach to them. Check the catalog for what SAT II tests are required by the college.
Most catalogs also offer an average or median test score of successful applicants.
Standardized test scores alone will not get you in or keep you out of the school of your choices. Your essay or personal statement is your chance to take control of the application process and express your individuality. This is an opportunity to reinforce a strong high school record or explain a weak one, to highlight special talents, or to talk about an experience, person, or event that has been important to you. Take another look the next day. Recommendations really help your application, especially if they show that the person writing knows you in some depth and comments on your personal strengths and abilities.