Road & Track has a photo of Tony Stark’s GP racer from Iron Man 2! The magazine says:
This is the Stark Industries-sponsored vintage race car that the movie’s main protagonist — genius inventor and swashbuckling lady’s man Tony Stark — will be driving in a scene that depicts him racing in the Grand Prix de Monaco Historique, a vintage race held in Monte Carlo. The scene is not being filmed on the actual streets of the tiny, glamorous seaside principality near the south of France, but on an elaborate set that replicates the Monaco circuit.
