Reading the forums will get you paranoid in a hurry. Intern's disease...
Remember, most people never mess with their car or tune it and most people never have a lick of problems with this car. Check out
https://www.truedelta.com/Scion-FR-S/reliability-1096 and see how good the FRS reliability is (the BRZ numbers are very similar) and for a TUNER car, these numbers are astoundingly good for reliability. On here are a lot of amateur mechanics and DIY tuners and guys who push the envelope. On here, there are enthusiasts and that's why you hear about problems. There's one thread for posting about how you have not had a prob with your car today, thousands for problems you have had. People don't come to internet forums to discuss how well thier car is doing, they come online to diagnose problems.
Relax.