You have an S3?all the Eibach ones seem to be fronts only when I look for them
Get new rears then .... Unless you like rough riding lowering springs, you should stay with eibach/OEM .... racingline and other brands seem quite rough .... I've run racingline R/S3 springs for awhile and there super stiff .... I'm swapping to eibach shortly ....Trouble is I have broken rears lol