Normal mode, ecu shifts gears where economy is the aim but taking into account how aggressively you pressed the fun pedal. On my Cayman s, I'd estimate 0-60 to be about 6 seconds in this mode.
Sports mode, speed is priority. Changes gears at higher rpm. Also opens exhaust valve at 3500rpm if fitted. Not sure if it goes all the way up to max revs, but I've only experienced/noticed it changing at ~7000rpm.
Sports plus mode, you have to change the gears, and it will let you into redline.