Hi Recosan,
I installed myself the SSL kit on my 2005 PLUS 4 in July 2017. A great improvement on the comfort and ride. No problem with the steering, the steering was lighter. The kit included bearings for the main spring sitted at the lower part of the upper spring.
First check at static ride if the lower rebound springs are free and have just a little play, they can be turned by hand without vertical play. If you have a trolley, lift the front of the car and release quickly the lowering valve of the trolley to drop the front of the car and check.
The SSL kit allow to adjust the compression of the main spring in order to free the rebound springs. This is mandatory.
Depending of the position of the spacer during the assembly: High ride or low ride, the upper gap between the top flange and the locking ring is roughly 70mm (high ride) and 50mm (low ride) for a +8. (2017 documentation)
What configuration has been choosed? High or Low.
Nota: you can keep the previous washers/blades with the provided bearings if you have shimmy.
SSl kit (2017):
main spring 250mm length, 1.9 daN/mm stiffness ,
rebound spring 65mm length , 3 to 7.2 daN/mm variable stiffness
You can contact Daniel White or Peter Ballard.
https://www.suspensionsupplies.co.uk/
