Do these need a clear coat, or can I leave the carbon weave bare?

A protective clear coat is highly recommended. It shields the carbon weave from UV damage and keeps the finish looking fresh long-term. Without it, exposure to sunlight will gradually dull the weave texture and color.

How do I seal the edges where the panel meets the existing fender?

The panel edges should be sealed with a flexible automotive sealant or trim-gutter sealant before final fastening. This prevents water from pooling between the over-fender and your OEM fender, which protects both the carbon and your bodywork from corrosion.

Will these fit if my car has been in a previous accident or has aftermarket fenders?

These panels are designed around OEM fender geometry. If your fender profile or mounting points have been altered, verify the fit against your vehicle's current fender surface before installation. Use the OEM reference points as your guide for alignment.