I read the LED lighting upgrade article in your July 2014 issue and thought the following would be of interest. LED lighting is superb. Once you have LED landing lights, you will never be satisfied with incandescent bulbs. Conspicuousness is improved. You need not turn any lights off due to much lower current drain, and LEDs will likely last longer than you can ever fly your airplane.
However, there can be electrical and administrative problems as you alluded. I had excellently performing Lopresti Boom Beams on my TBM 700 perhaps 10 years ago. But, attempts to add them to my TBM 850 five years ago were defeated by significant magnetic flux errors. The plane was not flyable with them activated.
I switched to Whelan LEDs for landing, taxi and position lights. These were installed without difficulty and the plane passed several annuals uneventfully. However, this February the local FSDO inspector decreed they all had to be removed and replaced with original incandescent lighting, or my aircraft would not pass the annual. I had to purchase new outmoded bulb lighting, and underwrite the exchange at a total cost of about $2500. Meanwhile, the same LEDs were being installed by facilities in other states on TBM 850 aircraft. I hope other owners have not had this restriction imposed.