Should I retake my A minus class in my last semester? I am a senior who is planning on applying to psychology graduate program after a gap year.
In the past three years, I have been involved in research projects and also internships that greatly enhanced my understanding of the subject matter, and I believe going to a graduate school will definitely equip me better.

I am wondering if it is a wise move to retake a class (not a core class by the way) that I got A minus in. I have 4 other advanced classes that I am taking and I thought why not shove that A minus class in and get A. My intention is to see whether I can do better (slightly better...) this time.

What are the pros and cons of doing this, particularly when I apply to prestigious and competitive grad programs? 

I appreciate harsh snaps as long as they are provided with reasonable explanations.

To add more details,

Yes, my university allows students to retake classes regardless of the past grade obtained, and while it will still be showing the retaken classes.

I am an international student from a (Far) Eastern country,
I have been studying in the U.S for 8 straight years, and I believe, in regards to psychology, the U.S appears to have the most leading programs in the world. (this might be debatable so please excuse me if my conviction is terribly wrong.)

Also, I aforementioned prestigious and competitive graduate programs.
What I meant are Research 1 universities. 
Obviously, schools like Harvard and Stanford are in that long list of schools, but so do Arizona State University and University of Minnesota-Twin Cities. 

To be clear, my goal is to expand my knowledge and deepen my comprehension of the subject in where I have access to Professors, colleagues, connections, and resources with qualities. Eventually, I wish to obtain Ph.D but if it is too competitive and I fall short, I will go for Master first.

In completion of Ph.D, I hope to bring those experience back to my country where the discipline of cognitive psychology has been stagnant in general.

So, back to my original question,
I am wondering if I should retake the non-core class that I got A minus in my last semester as an undergraduate, when I have a room for another class to fill in. If I get that stupid A, I will be able to set my GPA to 4.0.

But that is all I get and if this works against my graduate application, I will reconsider.  

Thank you all for these valuable comments.
I will take each and every one of that as a useful advice.
TL;DR: Probably not worth it. Take something else and expand your horizons.

From a knowledge perspective, you're not getting anything out of this. You got an A- in the course -- on a transcript, that should tell any graduate school that you understand the material in the course.

So any potential gain here would be for your GPA. On a 4.0 scale, an A- is a 3.7. If that 0.3 is the difference between a 3.5 GPA and a 3.4 GPA, go for it. Otherwise, find yourself another class and accept that you aren't perfect (nor will any graduate school expect you to be).