Thanks Richard, Andrea and Tim.
The system on the HistoricRacing site does look very similar to the RossoCorsa version - could be from the same manufacturer. The homologation statement is interesting - because I want to do some events in one of the two cars that I need to replace the exhaust on - so I guess it's important to have one that's approved.
I think you're right - the quality doesn't always match the pictures. It's the online-dating situation (no personal experience with that - it's just what I've heard!).
I believe that the manifold and downpipe on my works car can only be removed with the engine out so I guess a similarly awkward one can be fitted at the same time. If anyone fancies giving me a hand doing that in exchange for tea and cake (and reimbursement of fuel) - let me know.
Thanks,
Justin.