There's Flatout Ultimate Carnage, which is an "enhanced port" of Flatout 2, so I would recommend starting with that.
Also, can I get a ticket for the GRID Autosport hype train?
Great, I just bought in on steam. Albeit running at super stable 60FPS, it performs like a 30FPS game. Looks and plazs horrible. 5$ down the drain, I guess. Don|t buy it folks.