I agree that many automakers get their inspiration for their new models from pioneer auto brands, especially BMW and Porsche which are known for their outstanding exterior outlook since they first emerged in the automobile market. They combine their very own unique features with the dazzling and prominent characteristics of other auto brands to create stunning end results. This has always been an ongoing development process not only for automakers, but for other product developers as well, like mobile phones and tech gadgets alike. - http://www.pmwltd.co.uk
Aside from that, they always look at the classics they have. Inspiration never ends. Looking at the performance level, body kits, original wheels, engine. All these have factors in making a new model from a known car company.