I installed these last summer with just wd40, socket set, possibly use a breaker bar for leverage or a really long wrench, torque wrench, jack and stands.
It really firms up the rear, you get better traction off the line, no slop in the subframe when turning and changing directions, it basically gives a tighter feel to the back of the car. It also really helps get the back end to slide more. It also gives it a much more predictable power slide.
Again with firm bushings, it translates to harsher bumps in the rear and more noise.
It took all of 30 minutes to install including jacking up the car.
To install, do one of the 4 subframe bolts at a time.
4.Put bushing in.
5.Put cap back on.
6.Redo bolt and torque to spec. ( I forget what it is now)
7.Repeat on other 3.
You can have 3 settings, max traction, drift, all around performance.
Mine are set at all around performance.