Help with coilover spring

[delcbr]

My car a BMW e36 m3 AST Coilovers handles terribly as soon as I encounter any slight dip on the road the front wheels leaves Tarmac completely whilst driving normally try that in a corner and the car jumps across the road it's scary I am using a 900lb spring which hardly compresses which also results in it not extending much either I don't know how to remedy this
If I jack the car up there is a huge gap between spring and spring platform. If I fit shorter or longer springs and keep the ride height where it is just now then all I altering is the threaded collar further up or down and jacking the car up will still reveal a huge gap I believe. Can anyone help me at all?

[delcbr]

The ride height is 317mm
I jack the car up the wheel drops down it changes to 343mm a difference of 26mm. Or 1"
If I push down on The wheel it changes to 355mm and leaves a 15mm spring gap between spring and perch.
Any ideas anybody?

[delcbr]

I am going to change to a 600lb front spring but trying to figure out how to get the shock to fully extend as the car flies over the road and doesn't hold onto the Tarmac.

[delcbr]

It's for doing track days on semi slick tyres. But can't get the shock to fully extend as there is a 15mm gap between spring and threaded collar.

[delcbr]

I bought it from AST but it's never been right contacted them again trying to sort it out.
I fitted it there isn't much to it. Also using pillowball top mounts.