- Welcome to the forum!
Replacing silver plated plastic with solid metal parts? Good Sir, that would be adding unnecessary weight to the car!
Seriously though, Suncoast Porsche has a nice site with lots of parts for your steering wheel: https://www.suncoastparts.com/category/981G2SINTKNOB.html
Just so you don't have to learn the hard way like I did, those silver steering wheel trim pieces are not removed by simply unscrewing the allen bolts. If you do unscrew them, be prepared to disconnect the battery, remove the airbag module in the steering wheel, and only then can you get the loose nut that fell into a crevice inside the wheel. It's nothing that hard to do, just don't attempt this after telling the wife that you'll be back inside in 5 minutes...