Starting to read up on problems for the mk4 gt tdi 150psd version, already see the problem with some is the DMF, is this down to milage done or abusing the car itself?

How much does the part cost to replace (labour i can sort out)?
Are there alternatives to replacing the DMF with an uprated one or an uprated clutch?


Also are there any others problems with this car. Still browsing the site but cant find that much info on common problems with them.

Any help is much appreciated
cheers

ben