I think you mean modding your actual console. Depending on what he is doing and how good he is at it then yeah. all it takes is for the heat sink to be slightly 'disconnected' from the GPU and CPU and it will over heat, or he uses a crap thermal paste. But if he doesnt take the motherboard out (like only putting in LED's) then you will not have a greater risk as to say putting in new fans, Wind tunnel and a whole new case.