ohhh yea do those ecu upgrade chips really save fuel economy?

I've been following along trying to figure out why anyone would want to replace a diesel engine with a gasoline engine especially in a 4X4. WHY?

Join the club Gary !

If you need a go faster truck wouldn't you just perhaps buy the one which is the easiest to upgrade without ripping the guts out of it. I mean, doesn't Toyota do a 2.7L petrol truck anyway ?