Do these need clear coat, or will they yellow without it?

Carbon fiber benefits from UV-protective clear coat applied after you receive it. Without protection, real carbon can fade and lose its visual depth over time. Sand and prep the surface, then apply your chosen clear coat system to maintain the weave pattern's color and gloss.

How do I seal the edges where the over fender meets the original panel?

The meeting edges should be sealed with trim-appropriate sealant or edge tape after installation. This prevents water and debris from entering the gap between the fender and body. Use flexible automotive sealant rated for paint or trim edges, applied during final assembly.

Is this wet or dry carbon, and does it matter?

Hand-laid construction uses wet carbon layup, which offers excellent durability and reduces voids compared to pre-preg methods. Wet carbon is standard for over-fender panels because it bonds reliably and resists cracking under body flex. The quality depends on proper cure and finish work on your end.