I had a pretty tough experience with my RS4 as well. I loved the car but became agitated with carbon build up, DRC recall, and replaced piston rings. All of these things were covered under warranty but it was enough to scare me from the brand and why I made the jump to the M3. I am curious to see how your third go around will be. I hope it's positive. Let me know if you remain issue free.
On to my story of Audi and the TT RS.
Which is why i bring up this statement as some of you are probably thinking why the Audi??? I asked mysefl them same thing when I was ready to write a check for this car back in January as I have had awful experience with my previous Audis (2006 Audi S4 25th anniversary quattro and a 2008 RS4). I loved these two cars until I started having serious issues...driveshaft melted from the exhaust on the S4 and the RS4 needed the entire engine replaced (luckily still under warranty, but had to bring it to 4 dealerships until the right one diagnosed it--InSkip they are fantastic).