Do these plug into the factory harness or do I need to splice?

These mount at the factory corner light location and connect to the existing wiring — no splicing or rewiring required. Just disconnect the old unit and snap these in.

Will the smoke lens reduce light output?

Smoke tint does reduce brightness slightly, but corner lights are marker lights, not primary illumination. If you're using these alongside upgraded headlights, the overall appearance will still be bright and functional.

What if one bulb burns out — can I replace it without removing the whole assembly?

Most corner light bulbs are accessible from the back of the assembly without full removal. Bulb type and access point depend on your specific setup — test-fit before assuming access method.