Intake Effect On MPG

[why?]

but Tooter's SRI is unique, especially with that massive filter/stack thingy.

A CAI will decrease gas mileage slighty, a sri it really depends. It also depends on how you drive, aka if you floor it all the time to hear the intake you will get worse gas mileage. But some people with more off the shelf sri systems have reported slight increases, however those people usually have everything else stock though.

The theory is that the stock box is ridiculous, if you free it up with a sri system that gets more air in, but doesn't really reach far to get colder air, gas mileage can go up slightly, or stay the same. If you get an sri that reaches for colder air, or get a cai, gas mileage will likely decrease. Some Eco modders have created systems to get the warmer air into the engine, which can increase gas mileage.