I tried some LED H4 headlamp bulbs just to see what they were like. Absolute pants I’m afraid, look nice from outside the car as the colour temperature is spot on but they give out not much more light than the sidelight bulbs, dangerous to drive by.
If you want a clean, bright, white light you need to get some LED/SMD sidelight bulbs, and then fit a 6000k HID kit for the dip/main. Don’t be put off they’re not that difficult to fit, everything is plug and play however you should only bother if you have crystal headlamp lenses, preferable projectors. An old style headlamp with the beam refractor built into the lense invariably looks crap with an HID kit and will dazzle oncoming drivers.