Inside the service book there is a list of codes on page one. These should tell you the list of things installed but to help you when looking at the car
Dynamic chassis - check by pressing the drive select mode (top left next to gear leaver) select individual. If it's got dynamic chassis then there will be an option for the suspension settings. I think it's the top one.
Headlight assist - Above the rear view mirror there will be a camera set into the mount for the mirror in the centre. Or if it's got lane assist there will be one on the screen in a triangular mount. Lane assist also gives little lights in the external mirror glass in the shape of a car, these will light up if a car is in your blind spot.
Sport and sound - Will have red callipers (this may be painted after market though)
Dynaudio - Sub in spare wheel plus dynaudio logo on tweeters in a panel
Park assist - Next to gear leaver middle right button will be present. if it's a blank it doesn't have it
Rear camera - Obvious when you put it in reverse
Climate screen - On the HVAC controls centre dial press the menu button on the lower half, there will be an icon on the bottom left of the main screen of some wires through the front screen, press this to heat it. There will also be a reddish/brown tint to the front screen. Car will also have advanced telephone connection and there will be USB socket in the centre arm rest.
