The Z32 AFM's have a higher resolution and more dynamic range than the stock GTR items.
What this means is that they can more accurately determine the difference between two air flows (resolution) and they can usefully measure less / more airflow (dynamic range).
In the real world this is good because when your engine is being tuned to suit the Z32 AFM's, you can adjust the fueling with a lot more accuracy across the rev range.
