Have an 06 530xi. What size are the bulbs are they D2S or D1S? It has the Adaptive Xenon Headlights. And if they are D1S will the D2S bulbs work?

D1S. D2S will not work, as they are completely different animals.

another way to identify this is the imprint around the headlight housing. There should be an imprint saying adaptive xenon around the projector housing and showing the bulb size.

The imprint could also be wrong.

The only way to be sure is by checking the bulb

Google Osram Bulb Guide.

While the on-line guide is usually up to date it's been my experience that some times - not a lot but sometimes - the bulb fitment changes mid-stream.

It's been my experience that taking the time to check out the bulb actually installed in your particular car is the safest way to avoid two trips to the parts counter!

sylvania's guide is not up to date in 10% of the cases, only way to tell is just look right at the top of your car's lights.

If they are xenon, you will know by the way they turn on and the projector, if they are D1S, then you will know by the label that says D1S/H7.

You can retro a D1S to a D2S, not sure if they are the other way around.