To sum that up, sport mode gives you 3 main things on a manual transmission 997:
- Hard rev limiter so you can hold the throttle at redline and bounce it off the rev limiter
- Linear throttle mapping which can help with heel-toe
- More fully disables traction control when you turn off PSM at the same time as you enable sport mode
All of these are most beneficial on a track and not so much on the street. I rarely activate sport mode for street driving.