Are you wanting to stiffen the suspension up?(Stefan is Paul Robinson from Neighbours BTW)

You haven't said what bushes, dampers and springs you are using.

On my ERST I have Spax PSX kit -40mm and polybushes all round.
My FRST has G-max kit and no polybushes.

The FRST rocks about if I shake the car, The ERST doesn't even budge.

Whilst i'm replying you haven't mentioned if the car is an RS or a low spec car with a turbo engine in, The RS turbo has different bushes & suspension, that the lower cars have/havent got.