This is interesting as well are the explanations. I am still perplexed as to the changes in the DME code to have a decent increase in power. We can start with the basics; Fuel, Spark and Air.
I can see all three areas being influenced to gain power from OEM code to the tuners. If the tuners use the base code and only manipulate targets, things can be off if the base readings are incorrect. I cannot be sure of which, but I suspect one or more of the sensors inputs have been rescaled with the later OEM code.
If the Lambda sensors are off, and the A/F measurements, a recal with new code could certainly introduce new found power.
If the knock sensors were overly sensitive, timing could be pulled 1 - 2 degrees, with all else being equal, can equate to a 20 HP dlta.
And the last area is air. If the mass airflow calculations are off, targets are harder to reach. However, this is not a controlled item such as spark and fuel and less likely to be the source of error. That said, VANOS control will alter air flow but not the measured value unless it is non-linear.
I suppose my question is if the tuners are simply changing targets for the VANOS, fuel and timing, etc. what do they see as the variable(s) for the power delats with old and new OEM code?
Regardless, I am glad to see they have the ability to recode using a newer base.