I just got an email from Big Mikes's Performance, that the Sto N Sho Quick-Release Front License Plate Bracket is now available for the 2017-2019 Porsche Cayman/Cayman S models. The price listed on the website is $94.99 and they offer free shipping in the US and Canada via USPS Priority Mail.
Right now you can pre-order, which I just did, and their expected release date is 3/29.
Here's the link
if anyone is interested.