One problem related to engine has been reported for the 2006 Volkswagen GTI. The most recently reported issues are listed below.
Owner of a 2006 vw Gti, threw engine code for known TSB regarding cam follower and cam shaft wear at the high pressure fuel pump. Mechanic inspected site and discovered that cam shaft wear/ damage was extreme and would require replacement of high pressure fuel pump, cam shaft, and cam follower all outside of warranty. This is a known issue and should have some extension on factory warranties from vw of America instead of expecting owners to pony up $1600-2400 in repair costs when it inevitably fails. For note of known issue, see vw TSB #2013147/8.