you cant buff out discoloration from carbon fiber, the part you have is made with poor quality polyester resin, wich is a yellowish color, but not noticed till heat or sun has been exposed,or the part is made of epoxy resin and thats a good quality resin but not for high heat application, you need vynalester resin, some poor quality carbon mat is also produced and when exposed to heat it will turn the mat yellow and not the resin, i clear all my parts a thin layer of clear is all that is needed as resins dont have uv protection,(resin is heavier then clear) in my experience this has solved the yellowing you always see in cf parts, a good question to ask the person who makes cf parts before buying is if they use a certified cf mat, all good carbon has a certifacation number by roll from manufacture, hope that helps, and if you need some repair pm me with pics and i will see if i can hook you up
