The power delivery of the tuned motors are different due to how far you can adjust some of the parameters from standard using AC Schnitzer's tuning system.
Details of both are here, but as I've said before - you don't buy a 116 to go drag racing so don't get obsessed about 0-60 times. In reality the tuned 116 pulls hard all through the rev range. I've been in one with AC Schnitzer test driver Manfred Wollgarten behind the wheel and I can tell you it was pretty impressive for a 1.6 turbo!
ACS 116 performance
ACS 118 performance