I have an A4 Avant 1.9 tdi sport which has the sports suspension. I want to buy some Eibach springs which are 30mm lower, but is that 30mm lower than standard or 30mm lower than the sports suspension which I already have. I don't want to fit the Eibach only to find hardly any difference. I know Eibach also do a 45mm lowering spring. Which do I go for please???