I just read all of his posts and didnt see him say anything about putting them on the outside. Plus that would be even worse than putting them on the inside, why would you put lights on the exterior of a computer? If he did, and if his case is in view of where he sits, hes gonna have a headache whenever hes at his PC.
Lights in/on PC = Waste of money, waste of time
and yes, lights do increase the temp in a case, theres been studys that show that they do.