You either get a good one or a bad one. There is no in between. Fortuanately my fiance's family has had 2 of them for quite some time now (97 & 2002 Jettas) and they have run perfectly. On the other hand, I have other friends that just curse their cars. The VR6 engine is a strong engine, but it is the electricals that are the headaches. If you ask me, I would stay away from a used VW without records. In my opinion I would just get her a 3 series. At least you will have the board and people you know who could help you out with any issues. Chances are you already know what those issues would be with a 3 series anyways, being a 5 series owner. VWs are nice cars to drive, but they could be a constant nag if you do not get the right one. If you are adamant on getting a VW do your homework, or else you will get burned.
Just my 2c
Brian