Has anyone installed the GT3 bumper vent (smile) in the 991 front bumper? Reninline makes a kit and it looks great. TIA

 

I'm not sure 'its worth it'; that vent serves two purposes on a GT3:

1) cooling/venting for the center radiator

2) front aero (reduce front end lift and smooth airflow over hood/bonnet)

Note the center radiator on the GT3 is canted at an angle to direct the incoming airflow up through the vent.

unless your 991 has the center radiator adding the 'smile' is worthless and w/o canting that radiator, you will not gain much aero value.

if all you want is to look like a GT3 ... then knock yourself out!