directly in regards to the 2007+ expeditions, i've tried various plug and play hid kits for the lights i have, and everyone one ended up being glaring, and giving me no USEFUL light, there was light everywhere, but not far up ahead where i need it to be, especially driving on a highway. All that i lit up was the car in front of me, from top to bottom, regardless of aiming.
I have since then retrofitted with projectors from
The Retrofit Source online: headlight upgrades for all applications
No complaints since then
I am commenting specifically on Gen 3 Expeditions, because i have one and i have tried various hid kits.
I have seen plug and play kits on some gen 3 expeditions around here as well, and i usually let them pass me, then i highbeam them until they leave the highway, because thats what the glare from their expy looks like to me.