I felt a little more power with my (removed) dyno, didn't notice gas mileage, because I replaced the air filter with the K&N before I went though the 1st tank of gas.
Current Ride 2015 GMC Terrain SLT
2nd Vibe 2006 Vibe AWD Stealth Monotone "Recon" December 2005 MOTM
Original Vibe: 2003 AWD Abyss Monotone "Darth"
GM/ASE Certified Parts Manager.