I found this website accidentally whilst looking for something else, and thought it might help someone:
https://www.blackwidowexhausts.co.uk/varadero-77-c.aspAs far as I can tell, they are true to the original design and have systems for all model years, but I would probably want to ask them the internal diameter of the front pipe before buying (it should be the same as the rear) and if the later version has a catalytic converter.
They don't list a separate link pipe (for fitting your own back box) but you could phone them and ask.
I have no connection to the company, and am not a customer.
D-Day