I have the TCP coilover suspension on my 70 mustang. I have the varishock option 2. I don't think there was a option 1 last year. The +/- dual adjustments on the shock is very good. I think my spring rate is 450 ft/lbs. TCP recommended the SR for my car on the street. I think they were right on with the recomendation. At the same time I put on a TCP rack. The TCP stuff improved my cars handling like night and day.