how much heavier are the oem front rotors compare the tow pieces after market rotors?

 

It depends....each company has different weights for the different sizes.

 

yes but do you know how heavy are the oem rotors? they must be over 20 lbs .i am asking because recently i hold on my hand a rotor from rx8 and seems to me very heavy .i wouldn't expected to be that heavy ,so i guess ours are heavier aren't they? ..