How Hot Can It Get In There

I recently aquired a 99 miata. Im going to be getting the 2001 headlights for it(98% getting them). I want to get more of the HID (purple headlight) look. I feel the blue xenon gas bulbs just dont give you that zest. I've been able to aquire some translucent paints, and am wondering is it ok to paint the projector lense of the headlight. Obvously, I'ld bake the lights and take the clear lense off to paint the projector lense.
And how hot does it get in there? I was wondering if anyone has any idea how hot it can get inside headlight housings.