You could always get some flat stock/sheet and TIG up the runners. When I was driving VWs, I had a buddy that made a manifold and airbox for his charged Jetta. I think he ended up fabricating his own runners....couldnt find tubing that matched the ports.
I got the aluminum for him

Thats my profession unfortunately........I beat it, bang it, weld it, buff it, and fabricate it into doors for ambulances every day.
