Where can I read about mapping using the S8 and also mapping
in general ?

I would like to know a lot more about mapping
How much is the ignition retarded at a given RPM and so forth.
Overrun; is the fuel 100% cut of over a X rpm ?
Why is it necessary to use wide band lambda sensor when mapping?
as I understand it the engine makes the power within the narrow band lambda sensor area? (I drive with a home made lambda sensor and stage 1).

Hope to learn a lot more about this VERY interesting area