Stock '04 WRX Rear/Front spring ratio = 119/163 = 73%
Stock '04 STi Rear/Front spring ratio = 195/224 = 87%
Tanabe Rear/Front spring ratio = 224/240 = 93%
Swift Spec R Rear/Front spring ratio = 275/285 = 97%
Swift Sport Rear/Front spring ratio = 151/190 = 80%
Steve's STi Rear/Front spring ratio 2014 = 14/12 = 116%
Steve's STi Rear/Front spring ratio 2015 = 11/10 = 110%

For handling balance improvement (less understeer), get the Tanabe or Spec R.