lol, sorry mate was more a 'thinking aloud' kinda thing, but typed!
As i understand it the crank pulley is harmonically balanced, hence why uprated ones such as the BoostLogic one are so expensive - getting rid of the balancing can do very nasty things to your engine.
Also my (limited!) understanding of underdrive pulleys is that they basically save a miniscule bit of power by making the component run a little bit less; surely not something that is particularly desirable on either the water pump for cooling, the alternator for ICE installs or the power steering for, um, steering (OK, I'm clutching at straws on the last one!)
As I say, that's my limited understanding anyway, would be nice if one of the site brainiacs could elaborate