It's going to depends on how the engine has been looked after. What type of oil used at what intervals, etc. If I went and looked at that car I'm take my compression tester kit and check the cylinders for compression.
For that many miles i'd expect the car to have a huge file of service stuff, even if some of it is just receipts for oil and filters if any oil changes were done by one of the four owners.
If there isn't a continous record of paperwork I wouldn't bother with the car, there are loads of MK5 GTIs out there, most are getting on now though so I'd spend the time trying to find as good an example as you budget will allow. If you can't find a decent one for your budget, I'd look for other models.
