Maglite 2 d cell, upgrade

Hi,
I have old maglite 2 d cell , planning to use it for backup flashlight.
But it is rather weak light bulb. Can I replace the bulb with something better?
If it is possible, I'm planning to order this new bulb or led from amazon or e-bay.
Which one should i pick?

Nite Ize 55 or 74 lumen drop-ins are pretty good. You can get them from Ebay/amazon or locally at lowes or home depot. The 74 lumen is of course a bit brighter but costs more and has less run time than the 55 lumen version.

X2 on the Nite Ize.

Another trick is to clean, clean, clean all contacts to get the best efficiency in the circuit, use some eneloop pro AA in adapters (for a slight up tick in voltage) and obtain an ultraclear lens from flashlight lens dot com if you want to stick with a light bulb. Maglite made some Xenon bulbs that come in adapters that are available at eBay etc and those are noticably brighter than the krypton bulbs were.
Not a huge jump in output, just much whiter beam so it appears a lot brighter.

Another good incan option is to get a couple 3AA to D cell Series adapters which triple the Voltage and use a Mag 6 cell (or 5 cell if you are willing to overdrive it some) Xenon bulb - very bright with about a 2 hr. run on AA Eneloops. The new bi-pin xenons are OK (you need to fiddle with them to get them centered for a half way decent beam), but if you can find 'em the old PR based Xenon Mag bulbs are just as bright, if not brighter with a far nicer beam.

So what is the best upgrade for Maglite 2d? Can i insert 3AA to D cell Series adapters and put > 1000 lumens LED such as (AdventureSportFlashlights XHP50 )?

All of my Mags have some form of Malkoff drop-in installed.