The biggest problems with these are vibration and aim. The vibration is easy to fix (foam rubber around the headlight).

As for aiming, the projectors are angled inward to fit in the housing, which means that the beams cross slightly (about 2.5' of beam separation at 25', should be about 4') instead of pointing straight ahead. Some people have also had to use washers to adjust the height. Even with these not being aimed perfectly, visibility is still significantly better than stock headlights.