Do I need to rewire anything to run these one-piece units?

Factory headlight connectors bolt directly in. If your truck is stock wiring, you're plug-and-play. If you've already modified the harness, test-fit the connector before final assembly.

Will the black housing get hot or cause condensation inside?

The lens seals the housing, so moisture from normal use shouldn't collect inside. If you live in extreme humidity or regularly submerge the headlight, inspect the seal regularly during your first season.

Can I paint or modify the black housing after purchase?

The housing arrives finished. Any sanding, priming, or painting will void the integrated seal—test on a small hidden section first if you plan modifications.