Just some quick impressions
The new colours are awesome: the game looks absolutely stunning, espcially the cars. The crumples in the bodywork also looks a lot more defined. Night time also looks a lot better. I also haven't seen any fog...
The cars don't seem to have changed that much. They're slower while not boosting, but you get boost easier and use it up slower so it isn't a problem. The R-Turbo felt the same, but tougher. The X12 felt like it cornered a lot better.
The broken flashing billboards are very annoying. The superjumps and smash gates are alright.