“I have 2 850s and both are lowered. On my turbo I cut the springs about a coil and a half to get the ride level I was shooting for. I run my cars on the track at Phoenix International Raceway and a stock 850 is a terrible handling car. I ended up cutting the rear springs even more than the front to get the car to sit level. The reason for this is when entering a corner under braking the front end would drive causing the back to come around. I had the only front drive car with an over steering problem. I finally ended up buying 260lb stock car springs for the back.
On my 850R I purchased H&R Springs from the Tire Shack for $214. They were much easier to install than the cut springs and the ride might be a little better.
Bottom line, lowering your car makes it handle noticeably better which is why you would do it in the first place. On the other hand they ride very poorly at slow speeds.”