I have one of the FM LOP (light orange peel) reflectors in my Mag3d and it really does clean up the beam noticably.
The main skills you need for a Mag85 is getting the parts together, since they're not always available. You need an FM or Carley drop-in reflector (easy swap), glass lens (easy swap), 3-to-D adapters (just drop in place of the normal batteries), potted 1185 bulb (replace normal bulb), nine AA NiMH of not too high capacity, and a charging setup. Some of those parts are hard to find. But once you get them, assembly is simple.
Even simpler is an MC60, which is not quite as bright as an Mag85. You just buy a stock Magcharger and replace its bulb with a WA01160. Frankly I think this makes more practical and financial sense than doing the work to get a Mag85 together. Cost is about the same and you get a more convenient light, that you can just drop into a charging cradle instead of having to remove nine AA cells from the light and charge them externally.
The amazing Jim Sexton (js) is selling some turnkey Tigerlight mods; I like these better than Mag3D/MC mods because of the smaller TL body. Watch the modder BST forum if you want one.
Finally, keep an eye on the Ultimate Stealth Light (USL) thread. It's a 2D Mag body outfitted with a custom NiMH pack and what looks to be a 100 watt automotive halogen lamp. If that thing ever really gets made and sold, it will stomp everything else out there. It will make a Mag85 look feeble.