Thanks both for the info. I'm planning to upgrade the engine at a later date, so trying to plan for something that will cope with around 180-190 bhp (2.0 Zetec, twin weber 45s, uprated cams and increased compression, mappable management and high octane fuel, although I'll start with the stock cams and compression just to prove the system, and 150-160 bhp should be enough to enjoy the car for a bit.
BDA, I would be interested to know who built those manifolds. I wonder if anyone would be interested in a group buy?
I found out that the ST170 manifold probably will fit the head, and I think it looks like quite a decent design, which could be easily adapted as it's mild steel.
My cousin's ex husband makes titanium exhausts for Ducatis. I'll probably ask him to make me a system for it in the end, but in the meantime, I'll start with a system made from some ex Renault Clio Touring Car racer exhaust bits that I acquired.
Pics of Titanium Ducati system from a race bike that he made - attached for interest. Apparently they're about 130 hours of work per system, because of all the bends and diameter changes.