I certainly need to increase my airflow some, thats planned after this harvest. However, if a 250w alone causes those temps in your box, then I need to stick with cfl. In my box, which is where I veg and flower, I have a hard enough time keeping the plants from burning. With the cfl I have to keep them at least 4 inches from the lights. Yes, I know more ventilation will help.I dunno what a jethro box is but if its plastic I'd say HID might be risky. My veg box is a medium sized plastic rubbish bin with one 65w and one 25w CFL glowing and growing. I have an 80mm case fan take away the heat and once my cuttings have rooted they go in there and love it. There is no way I could use anything else but CFLs in there. HID would melt it and a shop lights are too bulky.