Aw, geez. If OP is thinking one of the colleges with generous financial aid for internationals, that 2.5 won’t cut it.
Very few high schools drop the A range to 80. It will be an immediate flag something is off. Yes, adcoms know how schooling works around the world.
There are so many accomplished applicants from across Africa, who do not need to manipulate reality. I don’t see how you can pull this off. Are you going to write your own recommendations, too?