It also looks very similar to the one that I had in my old 86 VW Jetta. I'd follow Maxpowers advice and try to source one through a Lancia vendor.
I'm sure that a real KG Works boot would be very expensive, only because it has KG Works on the label.
Wow. That's wild. I'd never seen that on the K.G. Works site before. Thanks for opening my eyes to other options out there. The Lancia Delta HF Integrale was very popular in the UK so it shouldn't be too hard to source one from an English speaking vendor.