LED pods were from an 2004 Cadillac DTS.
Mirrors were found on Century/Regal.
LED Pods
I found that the mirrors with straight lines going up and down them were much easier to use/mod the heater than the other zigzag version
Up/Down heater
Zigzag heater
Upon trying to peel the heater in the zigzag, I found that the coating holding it to the mirror would have spots where it no longer covered. Illuminating the LED's would show the areas where the coating had peeled. It looked bad up close. Looking for a method of making holes w/o lifting the heater, I came across a set of leather punches. They don't actually cut, so I used a torch to heat the end and melt the heater with the end. This gave me perfect circles. Cleaned the goop from the circles and illuminated, perfect.
Placed the LED on and gooped in place
Gooped the backing onto the mirror, the final product is ready to be put into the car.