This is the 337 (20th anniversary) gti. Im in the process of replicating the front lip (valence).
This is my attempt. I used tamiyas two part epoxy putty. Two layers of putty and a little sanding. Next up is the two bars that go in the hole, and the rear deck lid (spoiler).
Let me know what you guys think. The pic doesn't do it justice, sorry for the pic.