The spring rate for the Corksport are 25% stiffer then stock. Ride quality is a bit bumpier, but not by much over stock. I agree with swerve, handling is much improved with the springs. For the CS, I posted a pic of the drop on my Skyactiv in another thread. CS claims a 2.25 drop in the front and 1.75 in the rear. I think for the Skyactiv (due to the lighter front end) its more like 2.1 and 1.75.
Not sure on RM, but I'm sure there are few people with them installed who can comment.
The RM springs are progressive so it's hard to stamp a spring rate onto them, however they do make a drastic difference in handling while still keeping the ride very comfortable. I didn't actually take measurements of my drop when I had the RM 1.25" but it seemed like it didn't drop the rear as much as the front. I had 1 finger front and 3 finger rear tire-to-fender gap.