Will these plug directly into my stock wiring?

Yes. The harness terminates at the original side marker connector points. Insert, clip, and you're done—no splicing or relay work.

Do I need to remove the bumper to install these?

Access varies by model year and whether your bumper is already off the car. Test-fit the assembly before committing to removal; most installs can be done with the bumper on.

What's the difference between crystal smoke and clear lenses?

Crystal smoke tints the output slightly, giving a darker, more integrated look. Amber light still penetrates; it just appears warmer and less harsh than stock amber incandescent.