The upper torsion (radial roller) bearings taking up 17mm depth will need shorter main springs unless yours have sagged, although removal of damper blades will mitigate to a degree.
The lower torsion bearings are only 3mm thick so if main springs have sagged the extra rebound side length may be an advantage.
Having said above I would strongly recommend the
SSL RS front spring kit which includes both springs, rate riser, upper bearings and Spax adjustable gas shocks to match. The kit allows allows accurate setting of rebound pre-load which should be zero static and with no play, as well as ride height options.
Some suggest the rebound side torsion bearings offer no gain. I can only say I noticed much lighter steering after fitting mine and kept them when I fitted the SSL kit.
