He's referring to the one way clutch style alternator pulley.
The best fix,is to machine the crank to accept the TDI crank gear.No more worries.If the engine is not in the car yet,pull the crank and have it done.
There is also an updated balancer for these engines.The one way clutch pulley will help it as well.
With the crank gear mod,new balancer,and clutch pulley,it is bulletproof,and smooth.