How to tell when coilovers are maxed?

[UNA91]

I'm abit of a suspension noob; how do you tell when your coilovers have been "maxed out" or as low as it goes? My rears don't have a lower mount to thread the whole shock assembly like my fronts do so i'll have to adjust them using the spring perch. Would the lowest be until the spring is beyond 0 preload and has some play in it?

And if i could go lower or higher, wouldn't my spring preload be all messed up?

[bennjamin]

What brand are your coil overs ?
If the front has dual adjustable perches then the rear should too ?

[UNA91]

They're ksport coilovers which car with the car from the previous owner.

It's this kind of design: http://ksportusa.com/b2c/grfx/support_coilover_adjustments2.jpg

All the models made for the ep3 by ksport seem to have adjustable perches, unless im missing something lol But am i righ to say that the max lowest would be until the spring is beyond 0 preload and moving around when the car is in the air??