Do these fenders require fasteners to mount, or do they clamp on?

These panels use factory mounting points and are installed with fasteners. You'll need to source bolts and hardware that match your original fender mounting holes — check your service manual or existing fender attachment points to determine the correct fastener size and count.

Should I sand these before painting?

Yes. Sand the surface with appropriate grit, wipe clean, and apply primer and paint according to your chosen product's instructions. This prepares the FRP for maximum paint adhesion and finish quality.

Will these work with my current fenders, or do I need to remove anything?

Over-fenders sit on top of your existing fender structure. Your original fenders stay in place — no removal required. Verify that your fender wells have adequate clearance for the additional width before drilling any new mounting holes.