Proturing or roadrace rear suspension

Just curious.....How is the torque arm tuneable?

Would not the reason to install a different suspension for ANY kind of racing is to be able to tune (for bite) the rear suspension for different tracks / varying conditions?

I am curious about the other brands also.....I see a lot of hardware...but no real ability to change much (other than ride height) if needed once it is installed.

Just want in to learn.....