yupp..actually the stiffness depends on car weight and own's feel.
some ppl think 6kg front 4kg back is to stiff, some say ok-ok only, some will say still comfortable..
but to be frank, it all comes down to you, whether you can live with 6kg front 4kg back or not..
i think there is a thread discussing about this. you may want to refer to that 1st.
cheers!