Wage/overtime rules

I've got a few questions on wage and overtime laws and was hoping some of you have had experience with these issues before. I've googled my brain out and looked all over the Dept of Labor and Attorney general sites.

1. Is there a law that requires I be paid the same as or within a certain percentage of coworkers with the same title/seniority/experience?
I am not a minority or protected class.

2. If I am exempt from overtime, (I am not certain that I am) must I still be paid straight time in excess of 40 hours?

3. What are the pros/cons of being exempt vs non-exempt?
Should I expect my employer to challenge it if I try to change my status?