absorber

i want to buy HR progressive springs 35/30mm its ok to use progressive spirings on the original shock absorber ? it will be comfortable?

Hi everyone i have just bought my first seat (altea)and have started to notice a strange hissing noise from the front passenger side shocker(i think??)When i go over anything i get what sounds like the gas escaping from the shocker.If this is a shocker is it covered on the manufacturers...