OEM rotors are all about light weight
1) being compatible with the friction material of the pad
2) so pulsation isn't a problem

Also don't use aerosol brake cleaner to clean rotors or pad surface.
Detergent and water applied with a scrub brush is the proper method

Also the proper way to break in new brake pads- thirty slow stops spaced two minutes apart from thirty mph using light pressure.

I copied this from STARTUNED