I havent notice anything positive about any aftermark intake on a stock accord other than it sound nice.
If anything, I think I lost power especially at high end. and the MPG is the same to me. I always keep my car on top shape when it comes to the engine, but it also depends how hard you drive and where u do the driving and also the psi in your tires. The best I done is 33MPG driving with no hurry. I do 500miles on a full tank in the highway that is. daily driving here in nyc I get like 23mpg with aggressive driving.
I regret so much getting rid of my stock intake.