I've got some injectors for the V8 S5 for sale if you are interested. I swapped them out when I did all the work on my APR supercharged S5..HAHA! That is hilarious. I just wanted to say thanks for the write-up. I did it about 2 weeks ago on my S5 I bought myself for Christmas. OMG, the build-up was way worse than what I have seen others post. Definitely, running WAY smoother. Now to get rid of the cylinder 2 misfire. Replaced the plug and swapped the coil to see if it moved. Still there but only at high rpm, so I am guessing time to replace the fuel injector.
PM me if you are interested..