No LED will focus properly in a halogen reflector housing, or for that matter in any housing made for a halogen bulb. Some projector housings can handle the single plane of light emitted by a LED better than others but reflector housings especially handle that poorly. This causes several issues, primarily excessive glare for oncoming drivers and excessive light on the ground close up to the car. This increases the perceived brightness to the driver while actually reducing overall night visibility because of how the human brain and human eyes work. Our eyes are poorly built and our brains are stupid, let me explain.
When you light an area close in to yourself very brightly then try to look into the dark distance your pupils are constricted by the close in light which reduces the ability of your eyes to gather light. When an oncoming car has their high beams on and the rest of the world goes apparently darker this is why, turns out when your own headlights are aimed too low or just focus light in the wrong places the same thing happens. Then our dumb monkey brains make it worse, our eyes naturally drift to where it's easier to see which is where the light is the brightest. You end up washing out your distance night vision because it's too bright up close and your brain keeps putting your eyes down there up close, you don't look far enough ahead. At 60mph you're moving almost 90 feet every second but probably only looking 60 feet in front of your car if that.
But why does a LED in a reflector bowl only light up the road near the car more brightly? It has to do with how halogen optics are designed to work. The part of the reflector bowl that provides the farthest thrown illumination is nearer to the back of the headlight around the base of the bulb. Halogen filaments throw light in a mostly even orb with the hottest (and brightest) parts in the middle of the filament (HID are brightest at the ends of the arc near the electrodes). LED's put out the most light in the middle of the chip. Sounds good so far right? Here's where the problem comes in, LED's throw their light straight out with some incidental scattering to the sides depending on the lensing or lack of lensing on the emitter. Throw to the back of the headlight bowl near the base of the bulb is substantially dimmer than straight up, the area directly above the LED emitter creates foreground close in to the car illumination. Ok but the LED is soo much brighter so the light that DOES hit the back is still more than a halogen bulb! Yes! BUT remember, stupid eyes stupid brain, the now overly lit foreground negates those gains. Then you have this big gap in the light output from the LED substrate and bulb assembly and a bunch of light straight down that's too bright for the housing to properly control which causes a lit of upwards glare wasting light you can't use to see down the road and blinding everyone else like your high beams are on and RUINING THE NIGHT VISION of oncoming drivers too!
The best light for a halogen headlight is a halogen bulb. You can make halogen the best it can be by running a relay harness to reduce voltage drop and getting higher performance halogen bulbs (not blue tinted ones) with either slightly higher wattage (too high and you will melt/burn the reflector) or higher output per watt.
While not technically legal there are some bolt in projector options for running HID bulbs in HID projectors, I do this on one of my H4 equipped cars with excellent results using a G5R projector and a pair of used Denso ballasts. I have high performance OEM lighting on a budget with fairly minimal work involved that lights the road properly and does not blind anyone else (unless I high beam them because they're blinding me).
I realize all this will probably fall on deaf ears because HURR DURR MOAR BRIGHTER I CAN SEE BETTER YOU DON'T KNOW ANYTHING but at least I gave the information, what you do with it is your choice but please remember that on the road your choices don't only affect you. Your blinding bright headlights could cause a family in a van to hit a deer or have an accident because you ruined their ability to see at night with your headlights which are also ruining your ability to see at night.
