Trying to understand the functions is difficult as it refers to the SPS Plus.
Same thing. They discontinued the standard SPS switch so the only switches they have are basically Plus models, just "updated".
how do I know what setting Revo has installed on it ( default says B6 T2 F9 )
You don't need to plug the unit into the car - just switch to position 0, connect to computer, load software and "read" the SPS switch.
How do I know what to set the performance A, B and C to?
These are various settings. Realistically you should set these in conjunction with a rolling road or with someone who knows logging. You could have A as aggressive map, B as progressive map, and C as something else. I would leave F(uel) at 9, and T(iming) at 5/6, B(oost) can be anything from 1-9.
Take the SPS to the car switch on ignition, set the SPS to 2 ( performance A ) plug in , let it peep quickly for 10 seconds then pull it out / switch off ignition . how would I ever get it back to the default setting ???? if needed .
You have the stock map - just switch it to the appropriate number (can't remember off the top of my head).
Really am struggling to get my head around it . Has anybody written an Idiots guide ????
i do not have VAG . COM
You don't need VCDS but as said above, leave it with either what revo have it as (usually in map A) or the stock if needed.