crap
just a few points:
1) dyno's can differ quite a bit from one another.
2) my gues is all the box does is shift the incomming signal upward. so if its a pulse width signal it will listen to the ecu's incomming frequency of pulses and shift this slighty higher, thus increasing the pressure on the fuel rail thus increasing the fuel delivered per cycle.
3) i bet they didnt do a brim the tank test, because i recon the trip computer is just confused as the engine is outputting slightly higher power for less throttle.
4) i cant see how unless you custom map an individual engine and adjust the timing and fueling to squeeze the last drop of power out of each cycle, which would be slightly different for each engine, that just by increasing the fuel rail pressure your going to achieve any improvement in fuel economy.
5) oh and the last comment's were: they saw an improvement in emmisions, no mention of mpg, and you need to modify your driving style. well der, if i drive like a granny i can easily sqeeze more mpg out of my Toledo.