Will these plug directly into my factory wiring harness?

Yes, these mount at factory connection points. Verify the connector style matches your vehicle before finalizing the purchase — some years have different plug configurations.

Do these come with bulbs installed?

Bulbs are not included. You'll need to source H11 or similar bulbs based on your specific model year — check your owner's manual or contact support with your exact year to confirm the correct bulb type.

Can I use these with stock wiring, or do I need a relay harness?

Stock wiring will power these units. If you plan to run higher-output bulbs or HID/LED conversions, adding a relay harness is recommended to avoid overloading the factory circuit.