Yup, We have a lot of experience in these motors, feel free to drop me an email haydn@motorsport-HT.com
We recently finished up a monster build on the RS6 lump. Nickasil bores, custom pistons and rods, custom CNC heads, custom intakes, custom exhaust, dual Borg Warner EFR's etc etc. We made 1000+ Lbtq and 850hp. Note this motor is built as a DD not a HP big number lump, hence we can hit 35psi of boost by 3K rpm = 1000lbtq by 3K too.
HP is limited by the stock cams, we are working on a custom cam setup for high boost.
Here is a video from our dyno testing, this is close to the final tune but not quite as I didn't get good video of the last runs.