Do I need to buy a bulb separately?

Yes. This assembly ships without a bulb—you'll reuse your existing bulb or purchase one separately. Check your owner's manual for the correct bulb type.

Will this fit without any modification or adapter?

Correct. It mounts directly at factory points. No drilling, brackets, or adapters needed. Hand-tighten fasteners and test your low and high beams before closing out.

What if the housing gets dirty or cloudy inside over time?

The sealed assembly is designed to resist moisture and UV. If condensation appears inside, it's a manufacturing defect—contact support for inspection or replacement.