My understanding was that the G40 was built on the MX-5 platform, or used the MX-5 powertrain, but I now see that they are using Ford Zetec engines and, I think, their own frame technology.
If Mazda wants the MX-5 to be in the game, they have to put an N/A inline-4 with 200+ hp in it and/or bring it down to well under 1000 kg. Then, the MX-5 will start taking big bites out of the FR-S's lunch.
A Ginetta in the U.S. would be fun. It would bring us closer to some of the driving experiences of the 1950s-60s.