did the box come with the light? if your fan and exsaust running a good 'blow and suction' it should keep the light at a steady temp. ive used a 400w in a size that big before and no problems occured.i think it will be ok, exsperiment a little.you can always have the door ajar a little when the lites are on to exsaust some of the heat, but your fans should be sufficient
