Do these require any adhesive or fasteners to install?

No fasteners needed. These covers are designed to snap onto factory handles using the existing handle geometry. Test-fit on one handle before committing all four.

Will these work if my handles are cracked or heavily worn?

The fit depends on your handle's shape holding its form. If handles are bent or severely damaged, the covers may not seat flush. Inspect handles before ordering.

Do I need to paint these before installing?

These ship ready to install as-is. Paint or finish them only if you want a custom color match. Standard finish is factory black ABS.