Do I need any fasteners or adhesive to install this?

The glass seats into the factory mirror housing — check your owner's manual or a parts diagram to confirm whether your mirror uses clips, adhesive, or both. Hardware not included with this lens.

Will this work on both sides or just one?

This is a right-side lens only. Order the left-side version separately if you need a pair.

Can I paint or tint this lens before installing it?

Painting or tinting mirror glass is not recommended — it compromises visibility and safety. Install as-is or source a pre-tinted unit if that's your goal.