Will these bolt straight to my Colorado without modification?

Yes. These mount at the factory headlight mounting points — no drilling or bracket fabrication needed. Confirm connector type matches your model year before purchase.

Do the LED U-tubes work as daytime running lights or low beams?

The U-tubes function as daytime running lights. Main beam output comes from the projector lenses. Both operate independently through your vehicle's lighting harness.

Are bulbs included, or do I need to source them separately?

This assembly ships with the projector and U-tube LED elements integrated. Verify bulb type compatibility with your Colorado's model year before install.