Purchased my 2011 B8 S4 new in 2010. Scoured the forums to help me with the build (sports rear diff and B&O sound added and were great recommendations).

Just hit 175,000 miles. Kept it stock except for brakes (power slot rotors, ss lines, hawk hps pads) and wheels.

Amazing how solid of a car this has been. Granted, mostly commuting miles.

Apart from scheduled maintenance the only issues were a few of the common ones: Thermostat at 60K, finally bit the bullet and had had the PCV done at 150K. Other that that: LF wheel bearing went at 120K, hood latch sensor and hvac blower motor went at 130K, a few minor oil leaks (valve cover gasket and a few others). I'm most impressed that the DSG has lasted this long - I did get it serviced every 40K. Suspension definitely needs doing now, but it's not horrible.

Fingers crossed it lasts me a bit longer, but if it blows up tomorrow I can't complain! Considering the reliability, sort of makes me want to stay with Audi for my next car even though I'll likely try something new.

So, for folks looking at the B8, here's one vote that these cars can last quite long if maintained.
Cheers.