a street car isnt going to see any cavitation even if you red line a lot. I noticed that my car revs quicker with U/D pulleys on (probably due to the fact that the MR ones weigh 2lbs less then stock).

 

So does anyone sells pullies that are not under drives but weight less

 

I believe the Atkins serpentine set has lighter pulleys. They are all made out of aluminum, so they should be. Also, the serpentine belt grips the pulleys better, so not a chance of th ebelt slipping on the water pump.