Little late to the discussion, per usual.

Yes, K/N filters help. Especially on a tuned car. I was somewhat surprised. Not a first choice, mind you. It's clearly apparent VAG engineers were cramped on space with the intake plenum design. I'd bet they are relying on the intake suction/vacuum under boost to help Pull air in. My motorbike has a bigger air filter and makes 1/3 the HP per cyl. bank of a mildly tuned RS6. RS6 must have the smallest filter area/volume of any such car at said displacement and power. Egads.

Revo is a serious compromise "tune". Don't care for the power delivery, but at least it doesn't lean out on my car. Thanks to LSWING who helped tweak a few things when I first got the car. Made it livable and didn't genuinely worry about the trans as much (reduced torque surge; smoother mid range and something left at the top end). No luck with trying several times in contacting REVO a couple years ago. I just couldn't see bringing that product line in. (Maybe if I was a trans shop, however)

Have since driven Eurocharged and Viper tunes which are eons better in terms of power delivery (smooth and progressive).

The transmission won't last long w/o a tune and a full maintenance service. Classic chain of events that often catches people off-guard.

Good luck, have fun and be especially nice in getting to know your new "Autobahn Brawler".