Rear wing? Why are they all carbon?

I’m looking to add a slightly more aggressive/larger front splitter and rear wing.

In relation to the rear wing, why are they all carbon and thus expensive?
For example, Reverie or this at H111… Exige S2 Carbon Fixed Rear Wing Exige S2 (Curved) | Hangar 111

I’m not fussed about carbon and want to keep the original mounting position on the hatch (not mounted on the clam)

Are there not any other options, I can’t find any via Google?