while i dont have experience with campy, i have installed aest pulleys (china made with a us distributer) on 2 newer 105 derailleurs and 1 sis light action derailleur. on the newer one, a 5700, the 11t bolted on with no issues or adjustments needed, on the other newer one, a 5600 which there was alot of adjusting to be had. i assume that was due to moving from 10t to 11t, the b-screw, high/low limits, and index adjustments had to be played with to get smooth shifting. on the older light action sis derailleur i had a bunch of problems. first the inner bushings of the new pulley would not fit over the shouldered pulley bolt, a standard bolt would not work as it over tensions the pulley and it will not spin, you could use a nut on the back side but it comes really close to the spokes. then the larger 11t pulley hit a nub or guide on the back plate, a quick dremel pass and now it spins freely. i used the existing shouldered bolts without bushings, the space difference is almost incomprehensible, like less then 1mm, if i have time to file down the inside of the new bushings then i will but until then i think they will work. some would say that .5mm difference is too much but for me its close enough as the existing pulley bushings had play from use anyway. again, not campy but in relation to installing pulleys maybe you can grab some useful info from this. also some aftermarket pulleys have play, some do not, the ones without play or lateral movement will take finer adjustments to function to your preference. have i noticed a improvement while riding? no. does it look clean and really cool? yes.