I also checked OEM spring rate for older GT-R(stiffer). They are 16/9 kg/mm. The spring rates from Ohlins were about the same. (this means older GT-R is similar stiff ride as aftermarket coilovers)
GS F Ohlins coilover spring rate : 16/12 (kg/mm).
Maybe for me (coilover lover) GT-R is better choice because I don't need to buy additional coilover...