post 2011 1.4 TSI engines were a bit more reliable than earlier versions but they're still a bit of a dog. I've now lost count of how many rebuilds/piston replacements/timing chain failures we've had to do. At one point it was a couple a week.
The 1.8TFSI Audi will actually be a TSI chain driven lump which unfortunately also suffers with the piston/ring oil consumption problems. One of our staff cars has that engine and it drinks a litre of oil every 300 miles.
The later common rail 170 tdis are pretty good though as long as you steer clear of cheap remaps and cheap fuel, I have that engine in my Tiguan. Turbo actuator failures are quite common but I could sort that for you, I'm sure you still qualify for "mates rates"
... just avoid the PD 170 (up to mid 2008) they were never the greatest engines and now they're a few years old we see quite a few simple-ish but fairly expensive problems with them.. inlet manifolds are prone to leaking.. £££££!!