Ingo Noak Tuning
bought it straight from them many years ago and it was cheaper even with the freight shipping from europe, than buying from a US distributor.
It's fiberglass, and I had it along with the side skirts and trunk installed by a auto restorer.
Way back then, if i remember correctly, the problem with poly is that if it doesn't fit well you'll never get it to fit well. If you know how to work with fiberglass you can get it to fit well and you can repair it.
of course, for DIY, i would've picked the easier way which might by poly, but i knew i wasn't going to do it myself.