WNDSRFR, it looks like you found your own answers about the drag reduction but I'll throw in a picture that highlights the vacuum line. It's hard to see but it goes into the side of the control box. You can also see my custom double dump pack, which I think may expand the lifecycle of my batteries. (I relocated my starter to the trunk)
The pot on the switch probably adjusts how fast the motor ramps up before full engagement but as you said is probably not noticeable unless you can track the rpm of the motor.
Qwimby1 I agree the simplicity of instillation and modest power gains are appealing, I just think the price at the end was going overboard. I got my kit on 10/1/2014 at $1,850 +$150 for batts(plus a tuning solution) the base kit was $1,550 that Rob stopped selling. At the end you could add aux charger, and the Proceede which I don't remember how much those cost. But IMO it was getting too complex/expensive and moving away from this systems strengths at that time.
The torqamp has VAT which brings it over $3,000, +intl shipping for us in the states. It would be more but the euro has been loosing value compared to the usd. I don't think you could reasonably intermingle our systems due to the 24/48V system differences.
Rob was against putting our dump pack in the trunk due to the line losses of the high current load, but with the torqamp doubling our voltage to 48 it should cut the current in half letting you run smaller gauge wire to the trunk with fewer losses.
If the torqamp uses a button I'll have to give that one to the phantom. I would not like locking my hand in one location while I have to do all the steering and shifting.