[A4] suspension theory thoughts, questions, etc - grooved shocks

[Grant Lenahan]

>  With the Tien's that Taka mentioned, by varying the distance BETWEEN 
> the
>  adjustable upper and lower perches, you can increase the preload 
> (shorten
>  the distance btw perches) or decrease the preload (extend the 
> perches), then
>  ride height is dictated by where along the shock body the top perch 
> is positioned

So I'm really perplexed. What do you adjust the upper spring perch on? 
What is it attached to that it can move on?
If its not the LOWER part of the strut, with some very strong 
contraption rising up, how does it pre-load? Push on air?

If no, then it pushes against the car. But this is silly, the car is 
already pushing down on e spring with a force = MA where A=G or F=MG, 
the basic law of gravity!

My head is spinning :-)

Grant