What are the best springs for Bilstein Group N dampers?

[Jackzillaaa]

Hello, I have an 03 Saxo VTS and have recently purchased the Bilstein Group N Tarmac Dampers (front and rear).. I have been speaking with Faulkner to get some fast road / track use springs made..

I have done a bit of research and i'm thinking of 185lb springs..as I the Eibach/H&R springs are too soft. I am wanting to minimise body roll.

But I am wanting to lower the car -40mm lower than standard (on the front, I will lower the car -30mm on the rear).

But I am unsure on what length spring I need?
Faulkner seem remember selling a set of 7" 185lb springs for a saxo earlier this year. But they could not tell me how much this lowered the car...or how they performed..

Also, is there any way of checking what mm torsion bar I have without removing it?

Any help would be extremely appreciated.

Thanks, Jack