I have a UD pulley and an efan. After these mods I smoked D in the quarter. You should have seen him cry! Beat down by a 3.0! Okay, that's not entirely true - Marines don't cry.
Seriously, the pulley gives a noticeable increase 8-10HP. I haven't had any charging issues. I just have the single crank pulley. I didn't really notice any power increase with the efan, but I did gain some MPG. The fan runs off of a thermostat so it doesn't run continously and I have an override switch wired in so I can turn it off on long highway drives. BTW, the tuner rocks.