have you ever touch RAM without heatsink when they are operating? it is hot, yes hot.. if u still wanna repaint your heatsink, i'll suggest you to buy the paint that is heat resistant.. otherwise, the paint might peel off after some time.. or it might produce some burnt smell or worst case scenario the paint got melt up and might damage your CPU.. just be careful and take some precaution.. if you can spare few bucks, buy another ram heatsink.. just the heatsink only.. spray it with your desired colour and use it with your RAM for some time and see the outcome.. if nothing is going wrong, then only spray the mushkin heatsink..