I think you are reading it correctly. From all the research I have looked at, when speaking specifically about the A6, the K&N doesn't increase fuel economy or hp to any significant level. That isn't to say K&N is a bad product because I know they do help on many other vehicles, but for the A6 it doesn't look like it really matters. If anything, maybe that is a testament of the engineering prowess of those at Audi where their efficient airbox design just cannot be significantly improved upon with an aftermarket filter.

The risk with the K&Nis with oil residue getting to the MAF. The benefit is it is the last air filter you would have to buy, so that equates to about 4 normal paper filters to make up the cost. (Not factoring in the price for the K&N cleaning and re-oiling kits). I would say if you are the type who does your own oil changes, then a K&N would be ok since you can check it and clean it every oil change. If you are the type to let others do your maintenance, then perhaps a K&N isn't worth it and you should stick with paper filters since they aren't about to clean your filter for you and you might never know how bad it really is.

I would recommend after cleaning a K&N that you clean the MAF after250 and1000 miles just for good measure. It takes all of 2 minutes and all you need issecurity torx bitand a can of MAF cleaner (About $7-10 at any major auto parts store).

 

hmm, A6 2.8, 99 year: Before K&N approx. 17.8 MPG. Now with K&N 16.4