Driving with the top down is an integral part of owning a Boxster. If it wasn't important to us we would own a Cayman. My wife and I enjoy a romp through the mountain twisties on our motorcycles almost as much as in our Boxsters.
To protect our hearing (yeah right like we consider that) we sometimes like to wear our full face helmets with built in two way com-links, and the radio turned up to 30.
I'll tell you something unexpected. Wearing the helmets gives us a freeing feeling that allows us to push the fun factors. I don't overdrime my abilities by any means, but there is a sence of freedom when driving and riding with helmets on that I don't have without a helmet on. That applies especially on the motorcycles.
Don't get me wrong here, yes I sometimes ride without my helmet, but when I go out knowing my plan is to ride hard, it is on for sure. My personal motorcycle safety ethic dictates to me to wear a helmet probably more than 95% of the time.
Besides, since I ride year round it keeps my head warm.