mines done 140k and hasn't needed them,,, but make sure the timing-chain and tensioner that links the two cams as been changed,there's a member with A3 2.0 FSI ,just last week had one go been quoted £3700 by audi, mine went on start up last year was lucky it didn't make valve piston contact cost me £650,, dealers will tell you it's not part of any service-plan, doesn't matter it can and will fail !