Yeah JE, re: post# 107, lots of misunderstanding there. It was the same thing in the 70's and 80's with 4 barrel (4bbl) carburetors. The comment was, “Oh, a 4 barrel, that must suck back the gas”, when compared to a 2 barrel. Well, yes and no.
If you drove the 4 barrel the same easy manner you drove the 2 barrel, you would get better gas mileage with it, because the 4 barrel ran on only two barrels normally, and those two barrels were smaller in throat diameter than the two (larger) barrels in the 2 barrel, so you got better mixing and combustion efficiency with it when power demand was low.
When you kicked the 4 barrel hard, then the two larger barrels open up in addition to the two smaller barrels and voila, you get lots of power on tap, but you necessarily also consume fuel at a higher rate to get that extra performance.
Kick hard on the 2 barrel, and it's not capable of giving you near the performance, but of course it also is not consuming fuel as fast as the 4 barrel would at full throttle.
Same deal with the twin turbo V6 vs the normally aspirated V6. All that extra power has to come from the fuel, there is only so much chemical energy contained in the fuel, so, quite simply, you have to consume more of it. But you are still using less fuel, and getting more power and torque than a normally aspirated V8, which is not capable of burning fuel as efficiently as a V6, particularly when compared at low power requirements.