Originally posted by I_Wanna_Retire

what percent improvement to you expect in fuel economy for the 'economy' mode.

No data available for the VX, however, on the 5.3L V8 in the GM trucks there were minor performance gains and an increase of 3mpg fuel mileage. (that would have been close to 20% on my vehicle from stock)

Also, what is the 'tow/haul' mode buy you over the standard factory load?

in the `tow/haul' mode the bulk of the performance gaines are concentrated between 1000 and 4000 rpm, vs performance where the gaines are maximized between 4000 and WOT.

Etc.