Adjust cam to crank timing....how, why?

I have vcds. I already used it to make two great improvements. 1) stopped that annoying automatic door locking. 2) disabled the DRL feature.
I see where some owners here have made some cam to crank timing adjustment. Why is this done, and can this be changed for better performance using vcds? I am just interested in maximizing mpg since its my commute car.
It get 44mpg, and at 256K miles hardly burns any oil!

The search function is our best friend on this board. The word you are looking for is torsion.

Ok....will search, thanks.

No, really. I did the search function for you. Read through the thread I posted until you understand it and all will be revealed.