Besides the issues of incompatibility with the electronics of your car (easily fixed using relays) there are a couple of things you need to check before contemplating replacing your oem halogen bulbs with led bulbs.

1. Mounting. Does the oem halogen plug into a holder that has a proprietary fitting to the headlight housing? Example is the new hyundais. The bulbs are no longer held in place by a spring/latch arrangement. There is now a bulb holder that locks into the headlight housing. Since most (almost all, in fact) led bulbs have an extension cable then this holder can no longer be used and mounting the led bulb to the headlight housing will need modifications (if not impossible).

2. Is there enough space between the bulb and dust cover? Most led bulbs have a heat sink or fan that extends far behind the rear of the bulb. If you can no longer install back the dust cover you might end up with a dirty headlight and water inside the headlight housing.

3. Cut off. Cheap leds do not have compact light sources, resulting to highly unfocused beams that present much glare to oncoming motorists. Also, since the light is not properly focused then it also becomes useless to you. Malakas nga yung ilaw pera sabog naman ang buga, e di malapit din lang ang makikita mo.