Rev hang is both in the ECU Tuning as well as the mechanical parts on the car. The dual mass flywheel has substantial mass which will promote some rev hang and can only be reduced on a manual transmission car by means of lightening the flywheel.However lightening the flywheel does come with its draw backs if lightened too much. Too light of a flywheel will induce gear rattle / noise from the transmission and can also hurt torque a little bit at the expense of higher end power and the ability to free rev faster.So while our ECU Tune will help reduce the rev hang through electronic tuning, it can not be 100% eliminated.