My sister bought a '98 Golf and she just changes the oil every 5k miles and
uses VW/Mann filters and has no problem.  If your VW service department
doesn't understand your right as a customer to change your oil more often
because it makes you feel better (and couldn't possibly hurt the engine,
probably helps it) then just don't tell them you change it.  If you use the
Mann filters, they will never know.  You can feel better and your anal VW
service guy will rest easy as he mindlessly tows the company line :)

Ken Wilford
http://www.vanagain.com
John 3:16
Office (856)-765-1583
Shop (856)-327-0027
Fax   (856)-327-2242