The thing with Classics/Generations is that none of the toys have had formal licenses, but have typically approximated the original concept of the character.

As others have said, Cliffjumper isn't a Porsche, but has similar lines to the original vehicle to approximate the likeness. I remember it used to be talked about as a 70% rule - you weren't allowed to outright copy a design but you could homage it and approximate it but with enough differences that it couldn't be confused for the real thing. Think Universe Sideswipe, which resembles the Lamborghini Gallardo, but has the lights, grill, intakes sufficiently modified that it isn't a replica. On the flipside you have RiD Sideburn who approximated the Dodge Viper, but the likeness was so close that Dodge required Hasbro to obtain a license for future releases.

Because the VW Beetle lines and shape are so unique, any likeness would probably require a license, so the decision appears to have been that a small compact vehicle is the best analogue they can use - Classics, Titans Returns, Generations have all taken this approach. Unfortunately I do not see there ever being an official Generations price or scale figure that would meet the requirements you have.