I wouldn't touch the pulley's...at least not the crank pulley. Its got its own harmonic damper, and the aftermarket pulley's remove that, adding vibration resonance into the entire rotating assembly.
Whats that mean? Less engine life...for 3 hp. Woopdie do.
Now underdriving the accessory pulley's, thats dandy. I wouldn't mind putting a tiny one on the AC compressor, as I hardly ever use AC...as I'm used to owning a car without it.
Another thing you can do is completely replace the stock water pump (and its plastic impeller [weak point]), with an aftermarket electric one...thus removing an entire belt and pulley system on the drivers side of the front head.
But really in our car....almost all the power will be unlocked electronically. 220 WHP is obtainable (in an 6s MTX) without forced induction.