They make a direct replacement and it fits the existing CFL socket. You dont even need to change or disconnect the ballast. Same lamp is good for 42,28, and all the way down to 13 watt.So they got these 4" cans that have ballasts on the box plate with 1-4 romex in each can. They want to change to LED. I can barely fit my fat hands in the tiny holes. I think these may bid out at 20 minutes each to take out old can, remove ballast from wiring, add the new can with the whip and close up.
I looked at other ways to do it, but only drywall breaking will speed me up, so far as I can find. Any other ideas?