I often use this link to show how wasteful frequent oil changes can be.

Assuming the factory fill oil is 504.00/507.00, there's no reason oil of that calibre in this application needs to changed every 7,500 km/6 months unless you've modified the engine or something. The only proviso with these extended drain intervals is that you keep an eye on the oil level and top up if necessary.

Of course, being a fellow enthusiast, you might feel tempted to change it every 7.5k purely for peace of mind, no matter how misguided it is. In which case, for goodness sake don't go to the dealer! Learn how to change the oil & filter (if you don't already know) and do it yourself. You will gain much satisfaction from knowing how to take care of your car yourself, not to mention saving three crates worth of beer!