The pic you posted is definitely a composite using either a 3D model or more likely a car that has been shot in a studio using all kinds of slave flashes to create a smooth non reflective light on all the surfaces including the ones that should be in shade.
The sky is the limit with PS really. The package contains so much that the way to approach something like this if you aren't seasoned user is to search for tutorials on photo retouching. You should start to pick things up and at least know what tools to play with.
You can get goods results that don't look ridiculously overdone with just a few simple steps. Here is a shot of one of my old cars where I adjusted the levels and contract to make the colours more vivid, added a slight mid foreground blur and finally a light gradient overlay (top gear use filters on their cameras that do this so it always looks good on car shots)
