I wasn't proposing a stripped out GT-R aka Lotus, just some weight saving materials to bring the enormous weight down. Why do modern cars weigh so much anyway. I realise airbags, crumple zones all add weight, but whay don't manufacturers counteract this with light weight materials, probably cost.
Just as a comparison, and yes I've said this before, my Cossie weighs 1315kg. As a car it has 4 seats, is as big as a GT-R but the GT-R weighs 32% more than the Cossie , that's massive. I wouldn't compare a Lotus to a GT-R as they are totally different cars, but if you did the figure would be more like 50%+.
I know you weren't mate, just illustrating the different ethos at the respective manufacturers.
As for weight, it will be creature comforts. Leather weighs a lot more than cloth. Heated seats add cabling and heating elements. Airbag systems weigh a lot, as do extra fog lights, aircon units and onboard computers. The Cossie probably makes a very different sound when shutting the door to a Focus, as the engineering has moved on to provide what they perceive the mass market wants. Then you have idiots like BMW try and turn a 3 series into a 'lightweight' version by still trimming things in leather but putting carbon fibre roofs on cars.
Also, the cars themselves are getting bigger. A Focus today next to the Cossie would be quite a shock - I know, the lad next to me has a Sierra and even a Mk1 Focus isn't far off. The GTR would dwarf it! I guess it is all just development.