well the standard ford rs turbo came with 134lb front springs and 291lb rear springs so logic would say to keep some of the comfort i've just gone slightly harder and i did try some 200lb's on the back at first as advised by tony but that was shit as to much wait in car with full trim still in so we tried 300lb ones and they too are still a little off and my old 200's are now on the front of a fiesta with a zt in it with mtx box and that to is fine and handles well i'm not saying mine is the best just what i've tried and it could also be to do with the strut they are used with as most people use the gaz strut which is a compromise over build and cost were as i prefer quality and went for billies and have also removed all rubber bushes and replaced them with rose joints and solid top mounts so i can feel what everything is doing, i would be glad to hear how your cars drive and take bumps etc as i'm always looking to improve the feel of the car