AudiWorld Forums - 2014 RS5

What options, color and mileage? Unless it's a particularly rare combo, keep looking. They're out there. Just be patient and get the one you want. Overall it's a very reliable car. But like any car, no matter the make or model, there can be issues. I've had a very, very good ownership experience and haven't had a single issue with the car.

First and foremost, see if it has a service history. How many miles? The RS5 has some critical services that must be performed on time so make sure that's been done. I"m primarily referring to the transmission and rear differential. Both contain two types of fluid, ATF and MTF, and are changed at various intervals.
https://www.audiusa.com/content/dam/...ar-2015-v2.pdf

It is a high performance, precise vehicle so it will wear out consumables more quickly than say an A5. It also requires more maintenance.

There really aren't any known, regular-occurring issues, RS5 specific, other than the front brakes. Some people experience abnormal rotor wear rates where in Europe, they don't seem to have this problem. Other owners in the U.S. get normal life expectancy out of the rotors. Easily solved with aftermarket pads for the most part and there are lots of really good aftermarket rotor choices which are less expensive and as good if not better in quality. But it'd be good to get the discs measured and know how much life you have left.

Depending on the mileage, see if it's ever been carbon cleaned. If it's at 50K miles and hasn't had one, you might want to consider negotiating that into the price. Like all direct injection engines, carbon buildup on the intake valves is an issue. No way around it. I cleaned mine at about 50 K miles and it wasn't overtly terrible but the performance increase was quite dramatic.

Upper control arm bushings can go bad on any of the Audi 5 series and the RS5 is no exception. They're replaceable of course.
Other things that can go wrong which are Audi-specific and not necessarily an RS5 specific item;
-Mechatronic in the transmission. You have a 2015 and thus the latest version of it. Make sure when coming to a stop, in D mode, it doesn't feel like you're being rear-ended and pushed forward as the car goes from 3-2-1. A little bit of a push every now and again is fine but if it's going out, it'll feel like someone just rear-ended you. The gearbox should be a fairly smooth experience overall.
-Other gearbox related failures, usually sensors. The gearbox itself is extremely strong.
-Ignition coils going bad. Fairly cheap and easy to replace.

Other items I've seen come up have been fueling issues. They seem to be really rare but there are two individuals struggling with diagnosis over on the Audizine forum right now. There are a ton of active RS5 owners over there that can share their experiences. Just a head's up.

The engine itself is pretty much bulletproof and it's an amazing piece of engineering. I don't have a warranty and honestly, I don't worry about it. I have yet to experience any issues and I do all the maintenance myself at this point.

If you do a search, more info will come up. This same question gets asked every other month or so. Not a dig, just letting you know there are other threads with information. And if you get the car, stop by the Audizine forum too as there are a lot of RS5 owners who post regularly there.