Mad Max is my favorite action movie, and I agree that Fury Road won't be nearly as gritty as the original. Much like the the first Terminator movie, Mad Max's rough edges are what give it a more "realistic" feel.
That being said, from everything I've read about this so far seems Miller & Co. have done things the right way. Apparently (almost) all the car chases and stunts are practical effects as opposed to CGI, with green screen being used mostly for background and minor enhancements.
Also, this isn't a remake. According to the director the story takes place between Mad Max and The Road Warrior which is why the interceptor is still around.