[Christ]

If you wanted to get involved in this, to take care of the pumping losses, you could have someone machine a spacer with another throttle plate in it on teh two cylinders you deactivate typically. Wire a solenoid into the same switch so that when the cylinder injectors are inactive, it also kicks the throttle plate closed for those two cylinders.

You'll still lose some from the cylinder pulling vacuum against those plates, as well as friction losses from driving the valves still, but you won't be sucking/squeezing/[not]banging/blowing, anyway.