They are the stock wheels from a GT model, and are one of the lightest wheels you can get i believe!
i wouldnt call them lighest wheels you can get alot of the real tuning wheels are lighter
all in 18x8.5
350z rays forged 18.62 lbs
Cast RPF1 18.10lbs
TE37 15.6 lbs
Weds TC05 17.9lbs
ce28N 16lbs
OZ superlegger cast 17.7lbs
if anything for a forged wheel there very very heavy