I remember years ago guys did remove them on the 996 forum 6speedonline. They did other weight reduction measures as well. I don’t know if it’s really worth it on a 4S. No matter how much weight you remove from the car itself you still have that all wheel drive over the front axle.
I did up for the light weight package in my GTS. It is not just a seat removal . There are steering tweaks, suspension tweaks, throttle adjustments, glass adjustments, and I stopped short at the sport bucket seats which I really love but not in the daily.