After reading this thread I decided to simplify matters and posed the question to a company in Walsall, Birmigham....could they make option 6 or 7 plus a lesser build for people who didnt want such loudness or performance and a possible group buy...here is the response...
I've had a look at the video link you sent & had a read of your requirement.
We can difintely accomodate you.
The Group Buy sounds good, the best option would be to call us & arrange a booking.
We can work through & discuss exactly how to fabricate the exhaust system.
You can contact us on 01922 645 646, speak to the head of engineering IMMY.
Looking forward to hearing from you.
What do you guys think and what would be the next step? Maybe someone else might like to take this on as I have never organised a group buy before
Thought it might help us alfa owners!?