FSD dampers on -40mm pd100?

Does anyone know if this set up would work?

One shop says yes, the other no!:confused:

From what I can gather, the VRS is 15mm lower than a pd100 and the reccomended set-up on the VRS with Eibach's are -25mm, so If I get the VRS kit my car will be 40mm lower than a standard pd100

Is this right or am I getting mixed up?

The reason I ask is my local specialist says the FSD dampers will not work with my -40mm Koni spring but it will with the VRS Eibach spring set-up. Would I be wasting my money getting the Eibach's if overall, from what I can understand, it will lower the same.

Thanks people:)