Originally Posted by Wangwolf

RGB demon eyes and etched projector lenses are a thing. But I think they're kinda "ricey" and dont fit the e53.

Look at Lightwerkz work. Don't think he posts much on this forum anymore.
https://www.lightwerkz.net/photo/makemodel/bmw/e53/
https://www.lightwerkz.net/photo/
You can also get 10% off by using code code "junkie" on his site.

You could also look up e39 and e46 headlight retrofits and mods for inspiration.
Join the headlight junkies group on FB to see other people's builds. Or follow theretrofitsource on instagram