Will these lights plug directly into my existing wiring harness?

These come with the switch assembly included, so you're looking at a straightforward connection to factory locations. Check that your vehicle's wiring matches the connector type before final installation.

Are the H11 bulbs replaceable, or do I need to buy them separately later?

Bulbs are included with this kit, and they're standard H11 size — any automotive bulb supplier carries replacements when you need them down the road.

What's involved in the switch installation?

The switch assembly replaces a blank panel in your dash, so you're removing the blank and securing the new switch in its place. Test-fit it first to confirm alignment with your interior trim.