On the 99-00 headlights there is a little nub/tab on the bottom of the headlight (pictures below), I guess they might be on the NB2 assemblies as well. Does anyone know if the headlight will visibly shake if this piece has broken off (bugger snapped coming out of the hole)? I know they help "lock" the headlight in place, but do they do anything else? Besides this tab, there's the 2 bolts on the top and the metal tab at the outer rear, all intact. I'm working on a projector retrofit and would like stable lighting, not something that shakes like a half-assed project.

 

the NB2 headlights have big plastic tabs that go under the front bumper. I dont recall that little nub that you have. On the plus side I broke my tab off and my light has been fine. So I dont for see a problem for you

 

On my 2000 the tab is broken and has been for 5 years. I can move the assembly by hand but there is no visible shaking of the output using stock bulbs.

 

Cool. Thanks to both of you! I can slightly move my current headlights by hand too and nothing is broken, just wanted to make sure that this wouldn't really affect the overall stability.