I personally think you got what you paid for. Springs that lowered the car. A lowered car will handle slightly better than a stock car. If you wanted stiff, why did not you purchase coilovers of some type or custom order some stiff springs?
Read their website description for the spring: http://www.perrinperformance.com/pro...s/SPRINGS.html
They actually say that these springs will ride smoother than stock.
Do you have an evidence that the Perrin springs are softer? Did you have a compression test done on a stock spring vs a Perrin spring? What about track time? How do the two sets compare on the track when you are doing some real cornering?
But lets not get into a holy war. Some people like Perrin, some don't. I installed a Whiteline rear sway bar with Perrin endlinks. The sway bar has rusted but the Perrin end links look great. Both work.