The price of the factory fiberglass GT2 decklid can definitely turn some people off of going that route on their turbo – it is around $13k in parts to get everything OEM Porsche. Now, I am not one for replica anything for that matter, sometimes price does not justify difference in quality of materials.
Let’s talk about a company called NR Auto. Based out of Los Angeles, CA, they specialize in making high quality FRP (fiberglass-reinforced plastic) body parts for Porsche, Audi, Lamborghini, etc. Their GT2 decklid, https://nrauto.com/product/porsche-997-gt2-wing-for-997t997997-2-turbo/ is made out of fiberglass, similar to the OEM one, and is about $11k cheaper.
Now, you’ll obviously need more than just the decklid if you want it to be perfectly right. You’ll need 2x bumper buffers, 4x spoiler end caps, a GT2 rear fan harness (otherwise your OEM turbo one will work, but you will either have to cut the wiring for the spoiler hydraulics, or tape it up), and you’ll need the lower weatherstripping where it meets the rear bumper. Your latch and fan will swap over from your turbo decklid.