My wife has an old 4 D mag. I have tried the led bulb from Maglite and it's pathetic. I wanted to get a Malkoff like I have in my 6D but the serial # doesn't begin with D (What's with that, anyway? Why doesn't the Malkoff fit all mags?). What can I do that is simple to upgrade this thing? I've looked at the old threads and wonder if anything new has come down the pike.