[mark christopher]

there is a way to check weather you need a DMF, if its noisey then you should also fit a starter motor as these are the main cause of the dmf failing, it does not automatically need replacing, tho while the box is out....
you can get OEM parts cheap from a good factors, just get a good branded part LUK or somin like

solid flywheel transmits the torge exactly the same way as a solid flywheel!
the dmf aids nvh and gives a smoother take up of power, (releasing clutch)

id defo not recomend you try it yourself if you have no mechanical knowledge. you can knacked drive shafts sensors etc
take it to a reputable garage,