I have a York in my 4Runner with the 3.4.
Here is a little write I did:
http://www.ultimateyota.com/showthread.php?5324-York-for-the-3-4-liter&highlight
I've had a York on two different vehicles and wouldn't have it any other way. I'm not sure what the above posts are referring to but the 3.4 has no problem turning a York, in fact you can turn the shaft by hand and have it compress. My pressure switch is set a 140 psi and there is zero problem with it getting that high.
Second, there is no vibration and the noise isn't much more than a stock AC compressor pumping.
The Pacific Northwest Fab kit came with a combo pulley and there is a picture in my write up. I sent my stock pulley back to them as they had somewhat of a core charge but I was one of the first buyers so it was on the honor system.
They just sourced a pulley from Napa or somewhere and welded it onto the stock pulley. There is no sign of balancing in the way of grinding, etc but it has seemed fine since 2008 and many miles and probably a couple hours of use pumping air.
Their kit was pretty simple and kind of cheap in some places. The actual bracket is an easy fab and could be done with measurements found in the York manual found online. The rest is a generic pulley (with bearing) for the tensioner, misc bolts, a battery hook and cable. I used my own battery hold down system and additional battery cable.
I only run the half gallon tank because of room but it isn't needed especially for just airing up. I can air up from 15 psi to 40 psi in about a minute per tire (265/75/16) at idles ~700 RPM.
For seating beads or air tools 1000 RPM is all you need. As long as you don't have drive by wire you can step on the gas, move the throttle valve by hand or stick a screw driver or something to keep the throttle open. I've had it as high as 1500 RPM for seating a 37" Military tire but it didn't need to be that high.