The software upgrade turns up the throttle response to 11 and so, if you bury your foot, the car will take a deep breath and then lunge forward (and a little sideways) on gusts of turbo boost and a blizzard of revs.
WSJ: 2012 Volvo C30 T5 R-Design Polestar Edition Review: The Spirit of Sweden Lives | Rumble Seat by Dan Neil