i'm not a big fan of underdrive pulleys... the reasons being (and i'll list the pros/cons for each accessory effected)
alternator:
pros: none. output amperage is electronically regulated, if you turn it slower, it takes more force to turn it, netting the same HP from the engine. Proof? The force to turn the alternator is mainly based on the electrical load. Weither it is spinning at 1000 RPMs or 500 prms the force i.e. HP to turn it is the same for a given electrical load.
cons: won't charge as well at idle.
a/c:
pros: none. like the alternator, the a/c compressor will net the same hp from the engine if turned slower... it cycles on and off, and it's duty cycle (on time) will be increased if it's turned slower. no gain here (just turn a/c off if you want to race anyhow)
cons: won't cool very well at idle because a/c compressor is turning too slow
power steering:
pros: very, very slight gain (less than 1 horsepower) from less mechanical loss, from the bearings in the pump... but once again, it's pressure regulated, so if you're turning the steering, it'll just take more force to turn the pump than it would if it was turning faster (think old car, that squeals the belts while trying to steer while the engine is idling, but doesn't squeal while the engine is revved up) also, the p/s pump doesn't do much if you're driving straight (takes very little to spin)
cons: less power steering ability at idle. more likely to squeal the belts.632
water pump
pros: very slight savings from pumping the water slower. (maybe 1 horsepower)
cons: won't cool as well.
i think i covered it all... yes, i have a bias against underdrive pulleys, or anything that has negative effects and has its sales driven by marketing lies. Really? Then why have U/D pullys been proven on Dyno's and experimentation by members of this board to increase HP and MPG's? Speciffically Aldive's extensive work (RIP)? You are entitled to your opinion.
an electric fan may save a tiny bit of power, but keep in mind they don't move as much air, This is totally false. Electric fan can just as much than a clutched fan, if not more. Also, by removing the mechanically rotating clutch and fan you are reducing the roationg mass of the accessories. Also, the mechanical fan is always turning taking HP from engine to turn, the e-fan only runs when commanded on (with the proper controller), saving the HP and thus saving fuel. The HP to create the power to run the e-fan only when needed is less that the HP it takes to constantly run the mechanical fan. so cooling is reduced, and many of them attach to the radiator itself, which is a horrible idea and causes radiator leaks. You can't say an e-fan is a horrible idea because someone doesn't know how to install one properly. if you get one, be sure it has a mounting bracket that does not involve attaching to the radiator core (with zip ties etc).
FWIW you're mechanical fan's clutch disengages not entirely true, the clutch slips, it always spins the fan, always when the engine is revved up, for the purpose of freeing up power (thats why you're fan doesnt roar when you rev the engine) fan's max speed is at about 2,000 rpm.