Yep. K&N is in mine.
Keep in mind however, that given the "smarts" of T7, changing the filter won't gain you anything in terms of power or torque. The ECU is set to produce a specific torque number, and will do all it can to get there in a WOT state. What you'll experience, perhaps, is getting to that torque number quicker -- in other words, that seat-of-the-pants quicker throttle response.
Doing a K&N with an ECU reflash is really the right way to go.
Now in an "old-school" engine (classic 900 for example), you would see a power and torque change as these older ECU's don't work the same way. They aren't looking to produce a specific torque number, thus HP number, and as such freeing up air, and adding the appropriate fuel to go with that will indeed produce a power change.
'91 900 Turbo SE Convertible
'93 900 Turbo CE #116, modified
'02 9-5 Aero SportWagon, MT
'06 GTO, modified
'08 9-7X 6.0 Aero. The fastest stock Saab I've owned, bar none.