From all accounts, combined with the other mods, it is a worthwhile upgrade.
Phil sent me this photo. My 900 is the same. I'm guessing but I reckon the 750 can't be much different and it's a matter of cutting along the dotted line and inserting K&N.
My 750 is fitted with dyno stage 2, k+N and high level ducati performance cans. It has the same mod as ziggi's picture shows and seems to run just fine. I don't know what it would be like standard as the mods were done by the supplying dealer before the first owner took delivery.
Just chop the top off, as per Ziggi's post. The Ducati Performance airbox lid looks just like that as well. You may need (probably will need) to alter the jetting slightly with the new airbox arrangement and filter. Oh, and get some earplugs - the induction roar is fantastic and very loud