To help you with the setup, I would like to give you the following setup information, as provided by Lutz our Porsche Nurburgring setup guru. Some of this information re: castor and camber will also apply and be useful for all 968ers, the height, bump and rebound settings are KW Coilover specific.
General Suspension Settings for Porsche 968 with 17" wheel & road tyre.
CAMBER
Road & Track
Front -1.5 deg
Rear -1.0 deg
Track Only
Front -2.5 deg
Rear -2.0 deg
CASTOR
Set to max available up to 9 deg Max appears to be 4 deg.
RIDE HEIGHT
Set to max lowering for track use as per instruction in fitting guide.
Measuring from centre of wheel vertically to the wheel arch, the minimum
measured distance should be as follows:
Front 310mm
Rear 330mm
Coilover Settings for KW Variant 3
BUMP ADJUSTMENT TRACK USE
Front ½ turn open (from fully closed).
Rear ¼ / ½ turn open (from fully closed).
REBOUND ADJUSTMENT TRACK USE
Front 1 turn open (from fully closed).
Rear 1 ½ turns open (from fully closed).
BUMP & REBOUND FOR ROAD USE
Front + Rear open all ¼ to ½ turn more than for
track.
The spring rates for the KW 968 Variant 3 are as follows:
Front Axle
Helper = 20 N/mm
Main = 60 N/mm
Rear Axle
Helper = 10 N/mm
Main = 50 N/mm
(The conversion rate into lbs/inch is 5.588)
As previously stated, the most important thing regarding springs is that the damper can control the spring, discussion about rates alone are largely irrelevant. Very stiff springs are only OK for very smooth surfaces and tracks without kerbs (ie. oval circuits) but will cause instability on UK roads and tracks. One of the big advantages of the KW Variant 3 system is the high-speed bypass valving in bump, this will open automatically when you ride a kerb etc. The bump adjustment itself is for low speed forces allowing you to control the pitch and roll under braking and cornering. The ability of the damper to contol the spring and the way it does this in both bump and rebound is key to making the car stable and allowing power to be applied through the corner. A setup that's too hard will result in slower lap-times and more trips into the gravel traps
Remember that the installation and setup is also of vital importance, a good setup confirming the above settings and using corner-weight scales to balance the car (set rear to lowest recommended position and adjust the front to make the necessary changes) is also vital.
My final comment would be regarding bushes. If
you are going to change from the std rubber bushes then the only way
to go is rose-joints, see: http://www.rotaprecision.com/
If you change from the std rubber bushes (rose-joints or poly-bushes)then
be aware that you will need to reinforce the body. The rear top-mount
should be linked to a welded in cage and the front strut-towers will
need full reinforcement (a strut-brace is not sufficient) otherwise
the forces that were absorbed by the rubber will be transferred in to
the body and you are likely to see broken welds as the body flexes (the
rubber bushes are used for a reason). Look a what's done to a well prepared
racecar to see what's needed.
I hope this helps.
Best regards
James. (Taken from the 968uk.com forum)