I did install a set in my Boxster and, as expected, they function as marker lights only and not blinkers. They still feel like an upgrade to me. Not only because the lenses on my OEM lights were looking a bit tired but also because the led's illuminate the whole lens, which looks better to my eye than the single bulb at one end of the originals.
You can see my install here -
https://rx19jones.wixsite.com/a-986-s