Why in the hell would you want to reduce an upward curve, upward curves just kill the ladies, it gives them a lot of pleasure due to rubbing of g spot, it stimulates the walls of the vagina directly with the tip of the glans, it creates an illusion of girth since it adheres itself to the walls better than a straight penis, it gives you the edge in some positions like when she is facing down with her legs close together and you ride her like a jockey :) .
A girl who I am currently seeing has been with a lot of guys and she told me that the fact that it has an upward curve, makes her feel like it has a lot more girth, and she also tells me that it makes her feel things that she hasnt felt with straight penises.