So, I'm currently sitting around 135,000 miles on my 2006 GTI. I'm actually starting to notice things more related to time than mileage (rubber hoses cracking, etc.).
Since I'm dealing with an early BPY FSI, my maintenance list tends to be a bit longer than most. I won't get into all the details because it's a big list, but my car in particular had most of its problems between 50k and 70k miles. Luckily, all of it was covered under my CPO warranty. Things like the new long block, dual-mass flywheel, and multiple high pressure fuel pumps would have cost a small fortune to replace on my own.
But, since those things have been taken care of, my car has been much more reliable. I just had to put in four new coils (only one was bad) that were in the car for 80k miles. Everything else has been routine (including new cam followers that you don't have to worry about with your TSI) with the exception of a new thermostat and G247 sensor that failed.
With the trade-in value for mine being around $4k if I'm lucky and private sale not much higher, I'm in the camp of keeping it until something super major happens and it will cost more than the car's value to fix.