Beedub said:clubsports are beefed up in numerous ways over the v3 units... gusset welded ARB tabs, beefed up internals to cope with the added stresses of slick tyres which they are designed around, the clubsport can support up to 700lbs linear springs too, why on earth you'd want to do that ill never know.
No, the 2 way clubsport and V3 are constructed the same way. Only the valving shims (as in the size of the creavases where the oil is pushed through) differs and is set for the different spring setting. But the strut is build from the same parts, same materials, same construction type.
The only thing where the v3 and clubsport can differ is in strut lenght but I think this is the same in case of the z4/z4m, as the springs are the same in lenght. (rear springs are even the same rate, same productnumber etc)