According to the Man behind the curtain at porsche the GT3 will be getting a whole suite of friction reduction. Solid lifter, Zero drag calipers, etc.

from what Porsche USA says it is getting new cyl heads but nothing specific.

http://press.porsche.com/news/release.php?id=963
(2017 turbo)
http://press.porsche.com/news/release.php?id=1018
(2018 GT3)

Can anyone lift the curtain as to whether or not the Turbo will be getting another upgrade? Or will it be the same until 992?