Peter from Germany is producing down pipes from stainless steel.
It is for a 2-in-2 exhaust layout without connection pipe.
Unpolished for 270,- Euros,
polished around 450,- Euros.
I expect he has some in stock or can produce them within a few weeks.
Pic shows the unpolished version.
I have marked the approx. 15° upswept end of the downpipe, which is welded to it. That makes it easy to fit just the silencers you like.