Underdrive pulley and cooling problems?

[Moorepwr]

Ok I'm suffering from the famous harmonic ballancer seperation on my stock underdrive pulley. I'm replacing it with Buschur Racing Underdrive Damper Pulley. Someone was saying that the water pump isn't rotated as fast causing a systematic slowing of coolant through the engine. Is this with all aftermarket underdrive pulleys or just this one. Tym isn't there until monday so I couldn't talk to him. Has ANYONE had this problem of overheating or has anyone forked over the money for the dampened pulley?

 

[Turbo Guru]

all if they underdrive the waterpump.

 

[RocketDSM]

I've been running the Unorthodox set (all of the pulleys) and there isn't a problem yet. I have a leaky water pump, but that's not the pulley's fault....