Look at the "Lighting" section on this site. Plenty.of talks about this subject. There have been a lot of improvements and lower cost LED lighting systems out there recently. Good reads.
Some folks have gone the route of just replacing the halogen bulb with an aftermarket LED bulb. It's a much cheaper option than replacing the entire unit.
I would offer a real life experience counterpoint.
I have to counter and say that this is not the case if someone purchases a quality set of aftermarket LED headlights specifically designed to replaced the factory halogens. Oracle and other manufacturers make LED headlights that are nearly plug and play, aside from having to wire the halos. No flash is required for these to work. I have the Oracles and the entire install took no more than 15 minutes. I paid less than $600 for the pair at the time. I'd say that's a fairly decent savings.
My, real world experience, advice: don't buy crappy LEDs and save money over OEM. I ordered the Oracle Bi-LED headlights, they are plug and play with the factory harnesses unless you want the silly LED halo. I didn't want the halo so it's not done. They installed perfectly and I did not have to adjust them to level. So I actually saved some money and got the same functionality. Even replacing the LED bulbs in the DRL and turns will still net savings. I gutted my fenders so that whole module is gone, I can not recommend AAL at this time but there are some other companies making fender chop kits.
