hey. im getting 18x7.5, 18x8.0 volks with 50+ offsets front and back. can anyone recommend springs that will drop my car without having rubbing issues?

right now, i can get tanabe springs but cant decide which will be best suitible for cali streets, the NF or GF? both are 1-1.25" drop but the GF are a little stiifer.

does anyone know the spring rate of the kg/mm race springs?