it seems like alot of people swear by them on other forums...to my knowledge arent they basically the same as the whiteline alk and avo caster bushings?? just metal and a hundred dollers more?? i could be wrong
I've driven a 2000 impreza with them and without them...and I think that they do help, but only if pushing the car really hard (ie, pushing so hard in a corner that you're tending to understeer)
You can use less static negative camber when using them though and get the same effect.
Personally, I found that if you are transitioning from dirt to pavement during the course of a rally-esque situation, it is good because it helps the front wheels grip a tad better when they are cover in mud. (Without the PSRS I had crazy understeer due to muddy tires, with it, it was bad, but not scary).
I do agree with Touge to some extent though, you can probably spend money elsewhere and get better results and unless you are going to run adjustable camber plates up front and do some really hardcore racing, you probably don't need them.
Although some people do swear by them, so I also think it depends on the way your suspension is set up overall and driving style.