one thing that wasn't mentioned yet. the higher K you go, the less useable light there is. in other words if you get a 4300k kit, they will be like stock lights, but hid. anything past 6000k, the light becomes more blinding to on coming traffic. if you do a search here, not to long ago there was a thread that when to hid planet, and one of the members here was doing a retro on a projector swap. they also sell kits for those, and from what i have heard have come a long way and very easy to instal. i did a bmw e46 projector swap about 4 years ago, and i would never go back to regular headlights again with my explorer. the output is that much better, and you wont blind people. the plus side to my swap, is i have high beam with a low beam bulb. the down side, there were no kits when i did mine, and it took a good 30 ish hours to make both lights.