I own a '00 passat and it's a great car. My own is a 1.9 TDI-116 ps(originally)....now it has some 150 ps

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What you should look for is that it has a goos suspension. I had ....still have...problem with the suspension. It's soft (very confortable) but not good for what's underneath the car(ex. oil tank).
Another problem....check the turbine...it the car was trashed it will break and it's really not nice

... I had to change it a year ago....By the way I had my car bought 3 years ago as a second hand.
ADvice....if you buy one...don't force all the horses when the engine is cold

...you'll get surprises...BAD surpises. ( the turbo blocks and you'll get realy scared...
Good luck on buying cars