3.6 v8 lowering springs

A wee question regarding lowering springs,
is there any similarity with lowering springs for 3.6/4.2 v8 with the same for s4 v8[c4] and or 200q avant, some h/r suppliers suggest that c4 lowering springs are also compatible for 44 v8 cars, but i thought the similarity was with the 200 q chassis, if anyone has experience and or some for sale , i will be interested.
thanks
chris