"the Supreme Court, in its 2003 decision in Grutter v. Bollinger ruled that diversity is a permissible objective for the use of racial preferences in admissions"
That's for a narrowly tailored program. An explicit quota would still be illegal (the Bakke decision was not overruled by Grutter) and a system of giving every minority applicant more points than other applicants would also be illegal under Gratz v. Bollinger, 539 U.S. 244 (2003) (decided the same day as Grutter v. Bollinger).