The spring rates are very important to what kind of driving you do and here is the break down of them. The 150 lbs are used for the drag racer in mind. The 175 lb springs are ideal for a street/strip application and of course the 200 lb spring rates are for the road racing enthusiast in mind. The coil-over kits should fit most struts.
Don't forget to pick up a set of cast/camber plates with the spherical bearings on them.