Will these lights work with the M5 variant?

No—these are designed specifically for standard F10 models. M5 bumpers have different pocket geometry and wiring, so test-fit before committing to installation.

Do I need to remove the front bumper to install these?

Mounting method not specified in the product data—access may vary depending on whether the lights mount from inside the bumper cavity or from behind. Get eyes on your bumper first to confirm the approach.

Are these lights functional or just cosmetic?

These are reflector lights, so they reflect light rather than emit it. They're safety markers, not brake or turn signal units.