[webber]

sure you can damage your lens a lens work with respect to power which is related to current and voltage so you can actually wear it down, just like you can wear down a cdrw drive but why the hell buy one if you are going to be be picky,
i have built a little closed box (out of plywood and stuff) and a fan (high volume) to suck the heat produced by the dc, through temperature tests in a 24 hour period the temperature variation is almost 10 deg cel. this is a significant drop and should prolong the life of my dreamcast but i still have a full warranty for another year on it so just before it goes off i will break it and return it (the deal is no questions asked at the mom and pop shop i got it from)

regards
webber