I ordered a set of 70mm led halos, but the circuit board would not fit in the diffuser, so I pulled the LEDs off of the board and did this. Didn't want to mess around with trying to find some that did fit or wait for shipping...I can be a little impatient when I've got my mind set on something.
Ballasts: absolutely. During my first lengthy night drive, the driver side hl shut down 45min into a 2hr drive. Luckily, it didn't kill the ballast. As soon as I got home, I moved them to the outside of the rear cover. So far, so good. I didn't post a picture because it isn't as pretty as the internal mounting, but will do so soon. I used the supplied mounting bracket which keeps them about 1/4 inch off of the housing so that air can circulate on all sides.
