I recently purchased some used s-tech on ebay that were advertised as 350z springs, but I found out they're actually G35 springs. The information I found:

Tein S-tech 350z (fronts are progressive, rears are linear) .7”/.6” drop on 350Z G35 drops will be higher
Spring rates in lbs 386/402 (final rates only, softer initial front progressive rate unknown)
Stiffer then oem by F+23% R+16% (see note at very top)
Transfers +7% roll stiffness to front


Tein S-tech G35 coupe & sedan (fronts are progressive, rears are linear)
Spring rates in LBS 358/274 (final rates only, softer intial front progressive rate unknown)
Stiffer or softer then oem springs by R+14% R-18% (see note at very top)
Transfers +32% roll stiffness to front


Would the springs work well enough, or should I return them?

 

also, i think the drop would be slightly less, since the Z is not as heavy as the

 

Return them. The rear spring rates is completely off and there might not be any height difference since the g35 ride height is suppose to be higher then the 350z