Do these use the factory bolt holes?

Yes. These mount at the stock bumper side marker locations — no drilling or bracket fabrication needed. Basic hand tools and a few minutes get them installed.

Will I need to splice into the existing wiring harness?

These are designed to use the factory electrical connectors. Verify polarity before powering on, but integration with stock wiring is straightforward.

What's the difference between the smoke lens and a regular clear marker?

Smoke lenses darken the appearance for a more modern look while the amber LED stays bright enough for safety. The trade-off is a slightly less translucent finish — perfect if you want that tinted aesthetic without losing visibility.