There has been some confusion with the DSG maintenance intervals on the RS 5 because it was originally different for US-spec vehicles vs. ROW. Additionally since the B9 RS5 has a conventional transmission, its service intervals are more widely spaced and it could be confusing when looking at service intervals for, say, the 2019 vs. 2015. Download this document and keep it handy:
https://www.audiusa.com/content/dam/...-Year-2015.pdf Change that URL to 2019 to see the recommended B9 RS 5 intervals. Also note the rear differential has its own service intervals.
The DSG sometimes has a tendency to downshift roughly when the powertrain is cold, and there have been a few software updates to address that issue. It's mostly sorted now, but occasionally and out of nowhere I'll get a rough 2-1 shift when stopping. It would make sense for Audi to program the box to just stay in second until the vehicle is stopped, but so far the updates haven't included that recommendation :)
For the brakes, the US-spec 2013-2015 RS 5 came with standard and carbon brake setups; the former has been the topic of much consternation over the years because Audi's stock pad setup didn't like clamping down on hot rotors (say, at a red light after exiting a freeway), and that caused uneven pad transfer onto the discs which caused nasty brake shudder. After four pad revisions the issue is basically sorted out. They now offer two different types of pads for the fronts; one is for 'comfort' driving and the other is a continued revision of the initial sole pad option (for non-carbon discs), meant for aggressive or "spirited" driving.
I prefer to stick to stock offerings and a brake job (without rotors) runs about $1500-$2000 factoring in parts and expensive dealer labor. Rotors will double+ that job and are better off replaced if they're warped or too thin. This is a heavy car and chews through both the stock pads and rotors more quickly than any other car I've owned.
Other than that, the car is pretty solid considering the underlying powertrain technology. Carbon buildup is an issue with almost every direct injection engine, though it has historically been worse on VAG cars. Hopefully they'll follow Toyota and Ford by including a port-side injector used in low load applications on future engines, but for the 4.2 FSI motor it's just something that should be considered as optional preventative maintenance. It's my understanding that currently no dealers will perform a carbon clean either under warranty or as a pay service.
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