Rennsport Reunion IV closes with Porsche 917s tearing around the track

Rennsport IV, three days of serious Porsche love at Mazda Racway Laguna Seca, concluded on Sunday with a half-dozen races around the picturesque track near Monterey, Calif. And while there were a variety of all things Porsche to see and hear through the three days, Sunday saw some of Porsche's most powerful race cars take to the track. It was certainly a case of saving the best for last.

CAR tech: how much F1 is in the McLaren P1?

We're forever told racing tech makes for better road cars, but is that true, even in the case of the £866,000 McLaren P1? CAR tech looks at the similarities between Jenson Button's weekend racer and McLaren's hybrid supercar: Gives you wings A Formula One car wins or loses by its aero package – and the P1’s a true aero car with a mighty set-up. It has the highest amount of downforce of any road car on sale – so you couldn’t get closer to F1 with number plates if you tried.

Cadillac ATS (2012) compact exec unveiled at Detroit show

Cadillac took the wraps off the new compact Caddy, the ATS, at an event on the eve of the 2012 Detroit auto show. The new Cadillac ATS is essentially a BMW 3-series rival meeting all the design and engineering criteria of the larger Cadillacs. Cadillac ATS: what's new The ATS is like a baby CTS - the Art and Science design credo has been upheld, with sharp creases and pressed body surfacing to give it the Cady look.