I always thought the "STB, flex-no flex" topic was an interesting one.
Back when I first got my S197, I decided to make some purchases based on what I did to my 2000 new edge: strut tower and a-arm braces. Instead of doing the research, I definitely made my decisions based on past experiences and what seemed popularized by manufacturers.
I guess I suffered from a little confirmation bias, too, and for a while tried to disprove it. After talking to some FR500 owners who actually track their cars, and seeing a couple for myself, I have not seen or heard one FR500 that ran a strut tower brace. They definitely might be out there...just haven't seen one. But for some reason (marketing, maybe, like someone alluded to), they are on the Boss 302R.
A couple years ago, I pulled off my Steeda STB based on my interactions with the FR500 guys. I was one of those that said: if the FR500 doesn't run one, I'll surmise that all the STB is going to amount to is extra weight...especially if I'm not a 10/10 driver right now, and am still doing the DE thing working my way up to "seat time".
I spent a little bit of time in the seat trying to figure out if I could "feel a difference" and - of course - I couldn't. The handling characteristics never changed on the same track after the only change I made was removing the STB.
Man, I'll tell ya, if I did it all over again as a budding DE'er, I would mod - in order:
1. Upgraded pads
2. Driver mod
3. Tires
4. Driver mod
5. Dampers
6. Driver mod
7. Springs
8. Driver mod
9. Sways
And the list goes on. Unfortunately, I kind of went ass backwards due to stubbornness and lack of education...to include the power mods. I learned my lesson.