For a while I had an issue with my ZKW Bi-xenon headlights being too dim. I bought new xenon bulbs but that didn't fix the issue.
I then read about headlight retrofit kits and decided to give RetrofitLab a try.
Here's the video to my retrofit process. I encountered a few hiccups but overall, I was very happy how much the light output improved.

ZKW Bi-Xenon Headlight Retrofit

Version en Español