A stunning pic of a beautiful Car there, Rob, but I think that is the G12 - the rear engined Racer with the Lotus Twincam usually fitted.
You don't meant the G4, do you - the front engined one ? Would be about the same size as an MX5, so physically it would work, but the Ginettta Factory are still making a modern-engined version of the G4, so I guess there would be copyright problems. Still a beautiful Classic which has aged well.
Anyway, we digress from the topic, and indeed from 'Z's as a whole, so I'll shut up for a change....