Dynamic indexing is a measure of actions per second required from the driver.
Most car manufactures aim for an index of two. So that's two inputs which most drivers can apply without thinking.
As a comparison, F1 drivers require a index of seven, hence the reason most of us are unable to drive a F1 car.
Modifying your car adds to the index, which is something many don't realize. Actual number is a calculation which we need to facture in... A modified index of around 4, so it's could be a risky area depending on the owners driving ability.