Ok i guess it depends what engine. However i would say the MOST MOST important thing when looking at any used VW is the service record. I know LOTS of people with dubs over 100k and no major problems other then normal wear and tear. Then i know people with insane problems at under 40k. Just make sure to tell him to get the service history. If it is the turbo make sure all oil changes were done with synthetic. I know the logitudinal 1.8Ts have oil sludge problems, not sure about the transverse though.

My sister has a 2.0NB, it only has about 35k on it, but it is running great. No major problems so far.

All dubs have thier quirks, but for the most part as long as the vehicle was taken care of there shouldnt be a problem.

In the Passat community 80k is around the time when the timing belt should be changed assuming it hasnt failed previously. If the car has 73k on it, then i would reccomend getting the timing belt, and maybe even the chain tensioner (similar to the timing belt, but on the back of the engine) done as well. All of this is coming from my Passat backround, but im ASSUMING some of this stuff would carry over to the entire VW line as well.

HTH
-Jordan