I have been very cautious about the whole LED thing, as my many decades fooling with the halogen and HID side have been quite informative (and not very profitable). To begin with, while LEDs are very efficient, their output and lifespan is a direct result of how well you can dissipate the heat created on the tiny little chip. The beauty of HIDs is that the bulk of that heat is taken out from the ballast - a massive heat sink with electronics potted into them and able to be mounted remotely to cool well. LEDs could be a lot more powerful - if they weren't so constrained by having to mount their heat sink in a place where there is not normally much if any cooling air available.
I have to admit, there are now SOME LED drop-in bulbs that can work (H4 being a good example). You have to realize that the geometry of the light source is critical down to thousandths of an inch, and not many times can the very directional LED chips emit where the radial pattern of a hot wire or the much larger spherical source of an HID can cross over from one to the other. Generally, the larger the reflector, the more foregiving the geometry - and that is why there is little chance an LED bulb can work in a reflector made for HID or incandescent sources. Hell, even going from a filament to an HID the geometry in the tiny optics of a projector don't work.
Someone mentioned earlier that LEDs can't work in projectors, and I have to say, that NOTHING could be further from the truth. Pretty much ever high end LED light uses projector-like lenses, many with no reflector at all (as the light output is already very directional. I have LED lights from JW Speaker in most of my trucks, and they are not quite a crisp a pattern as HID projectors, but functionally work very well and are fully US DOT compliant.
https://www.jwspeaker.com/products/heated-4x6-led-headlights-model-8800-evolution-2/
If you want legal bi--beam LED projectors in your car (legal in Canada where we can use ECE pattern) these are also available
http://www.myhellalights.com/index.php/products/auxiliary-lamps/modules/90mm-bi-led-module/
While I wish there was so low buck way of getting decent LED lighting, I have not found any. Yes, you can get cheap 7" round, 200mm rectangle and 4x6 lighting, but they are no where near the quality and beam control that the JW Speaker and Hella stuff is. Kiss at least a G-note goodby if you want just the main beams alone.