I dont see why the TPS setup i have couldnt be adapted to suit yours, all it is, is a small circuit, which produces the output to the relay that controls the clutch, depending on what you set the switch at, ie the voltage you want it to detect on the tps, the circuit would just then switch it on.
As for bogging down, i dont suppose there is, off boost, the car accelerate a tad slower, throttle responce is a tad slower, but i think that just due to the extra air ways and the restriction of the air path from the extra piping and the charger. But as soon as the charger kicks in, basically when you hear it whine, it just goes!
Ive also just had a scarey thought, if i ever have to change the aternator for one reason or another, id have to strip the whole lot off!