It really depends on the LED kit that you're trying to use. On more powerful LED kits with high outputs and high levels of heat, it's probably a better idea to mount the drivers/ballasts outside of the headlight. The Oracle H7 kit we used on our 2015 F150 XLT Project Truck is a bit more basic, and we haven't had any issues (so far) with having the driver mounted inside the housing for the low beams. As for the high beams, we had a few customers try to get the Oracle drivers inside the housing, but none of them have had much luck.