Good overall Cam Swap posting! Nice site. MetroMPG!
The only thing here I see that makes an incorrect assertion is where it is stated that "the smaller lift
and duration" is what makes the lower RPM cylinder pressure and torque increase. Generally, it has been found that higher lift will increase torque and HP without losing any low-RPM torque, and sometimes below-peak torque is also enhanced.
I'd like to think I could get a custom regrind based on a regular 3 cylinder cam that could handily beat an XFI cam in MPG, Torque AND Horsepower, but the HP might take internal engine mods. OEM engines are so far from optimized that a dedicated builder can easily make all aspects better with a little hard work and research. A great book (now out of print) Practical Gas Flow, by Dalton.
There is ONE Outstanding cam spec that determines engine responsiveness, torque and HP more than any other, can anyone guess what that is?
...or something else?