I ran across this very nice amateur level advertisement article from a worthy Bilstein Competitor - KW Suspension. Of note is the reference to and distinction made between Low Speed and High Speed Bump -- the part I underline -- that I alluded to in the first post of this long thread. I believe that stiffness with Low Speed Bump is beneficial (less front-rear weight transfer with acceleration and braking, less roll in corner) whereas stiffness with High Speed Bump is NOT (harsh ride from road surface imperfections, car going airborne when hitting bump). I imagine the million dollar question is how to separate the 2, but that is way beyond the level of my knowledge.
Explanation of Centre of Gravity movement and suspension movement and effects.
DEFINITIONS -
Bump = When a spring is made to compress.
This is also broken down into -
Low Speed Bump = Slow compression on the spring such as acceleration,
cornering and braking.
and
High Speed Bump = Fast compression of the spring such as kerbs or potholes.
Rebound = When a spring is made to expand.
EXPLANATION
When a car is travelling along the road in a stable condition at a steady
speed in a straight line the suspension and springs will be in a state
of equilibrium although the springs will have some load already on them
due to the weight of the car on each corner.
Things that affect the dampers and springs are acceleration, cornering
and braking, but also kerbs and pot holes, or anything that creates a
movement effect on the wheels or the car chassis.
ACCELERATION
When a car accelerates the front will tend to lift and the rear will
tend to drop. Partly due to the Centre Of Gravity(COG) being affected
by it's inertia and trying to stay where it is when the wheels are trying
to push it forward. Ever seen a motorcycle do a wheely, this is where
the power of the bike combined with inertia of the COG overcomes the weight
on the front wheel. Even on a lower power bike the rider can just give
a tug on the handlebars as he accelerates and this will be enough to pull
the COG back over the rear wheel as the bike moves forward. This is an
extreme example and not generally seen on a car because of the relatively
low power to weight ratio. Unless - it has massive power to weight ratio
such as on a dragster.
The effects are low speed rebound on the front and low speed bump on the
rear.
CORNERING
When a car enters a corner, the COG will want to move towards the outside
of the corner and will cause the car to try to roll over and if the car
had a sufficiently high COG with a narrow track it probably would. Thankfully
sports and high performance cars are designed to have a low COG and apart
from in extreme circumstances the COG remains inside the wheelbase and
track. So the car will simply roll within that area causing the outside
suspension to compress and the inside suspension to expand.
So in a corner the outside suspension is subject to low speed bump and
the inside suspension is subject to rebound.
BRAKING
When a car brakes, the front will tend to dive towards the road and
the rear will tend to lift as the COG is trying to carry on moving forward
over the front wheels which of course are trying to slow down. Because
of this another effect is that the COG (or weight) moves closer to the
front axle and so the front tyres take more of the braking force, in extreme
circumstances this could be up to 80% or even 90% of the braking effeciency.
This is one of the reasons that the rear wheels will lock so much easier
than the front, as the braking force between the pad and disc becomes
greater than the frictional force between the tyre and the road and this
can end up in a skid.
How is this related to KW suspension kits.
ON THE ROAD
Where you have adjustable bump and rebound on a suspension kit it means
that you can alter the amount of damping for each type of driving situation,
for instance if the car is being driven mainly on the public road it can
be set up for a softer ride so that acceleration, cornering and braking
are slightly more comfortable not only for the driver but also for the
car and this will give the suspension and fittings of the car a longer
life.
ON THE TRACK
When on a track the suspension can be set up to be a bit harder as the
track is usually a lot smoother than a public road so the emphasis is
on resistance to movement of the suspension and this will help to control
the chassis in pitch and roll situations. Which means that the car is
kept under better control especially when cornering and braking.
The KW suspension has a high speed bump setting which is set at the factory,
what this means is that although the low speed bump can be set fairly
hard, the high speed bump will allow some movement in the damper should
the wheel encounter something that would otherwise jar the suspension,
such as a kerb on a track or a pothole on the public road.
So with KW suspension it isn't so much a compromise as having the best
of both worlds.
--
Regards,
Can
997 Turbo + Bilstein PSS10 (Review) + Cargraphic Exhaust (Heavenly Race Car Noise 
Review)
...Thanks for the crash course Cannga 
LOL.
While it doesn't surprise me, it's amazing to think you could tune the Turbo to become such a track monster, and here I am half the world away cruising the same "baby" on congested Los Angeles freeways.
You could actually see some these things if you just look under your car. First the rear: 
Care to share your experience; where you get the thing from? Installation difficulty? Noise problem with the rigid mount? Is this THE TOY here: 
. I heard this is a very good upgrade sinc it eliminates completely the manual gearbox slack..
. Perhaps this is where the Bilstein's shock absorber is different from stock.
