Hey Salem, stock GTRs will sip fuel as much as if not more than a 5litre , I've tested this against my old VR stato . Since this has a free flowing air intake, exhaust, bigger pump, bigger injectors etc, if given a bit of squirt, will struggle to get to 300kms . Maybe if I got it tuned only and only for fuel economy and drove under boost then the mileage would be greater.
But driving a GTR for fuel economy would be like 'watching a porno for its plot'
Simple maths, turbo cars will consume fuel as much as V8s, but its not what you drive, its how you drive it. But to answer your question, both can be used as daily, as I had no trouble driving my car to work everyday and now occasionally.
Hope that didn't confuse you!