I just attempted this upgrade this morning and this is my experience.

The removal/re-intallation and modification of the tail light housing was very easy although I had to take a different route. My hole saw was a little too big in diameter and I was afraid of breaking my wrist. I noticed that the plastic already had a molded in counterbore of the correct diameter and that the top 1/4 of the "plug" was not connected. I did some additional scoring of the plastic, inside of the counterbore, and carefully broke the plastic with a needle nose plier. The plastic naturally wants to break at the scored C'bore diameter. This went very fast and I just cleaned up the plastic with the exacto knife.

I was not able to solder wires to the metal tracks or get solder to adhere to the tracks at all. I suspect that my soldering iron is too small and I will re-try with a larger iron. If that fails I will drill & tap the tracks for 4-40 screw and make the connections with ring terminals.

Rich