Looks like you bought them... cool.
How stiff are they?? Well I think the stock Focus Central spring rates were 175lbs front and rear. Compared to stock, that's a little stiffer in front, and should be much stiffer in rear (which is a good thing since you won't have a rear sway bar). Don't forget that stock springs are about 150-170 in rear (just remembering numbers off the top of my head) and now you're going to have 175lbs directly on the rear strut. So that means to have a spring in the stock position on the control arm mimic 175lbs on the strut itself, it would have to be much higher...maybe 250lbs??? Not if i explained it properly....
I drive in Vancouver, Canada and the roads here are pretty good all year round. To put things in perspective, I bought 400lbs springs in front and have custom 220lbs springs in rear (overall the stiffness feels the same front and rear), and I also have the 22mm front and 25mm rear swaybars. PM me later on when you're used to this kit and the spring rates. If you want to go stiffer, it's super easy and cheap!...although you have to pay attention to the overall length of the spring.
For example: stock spring you're getting in front is 175lbs x10" long. My 400's are 7" long.