The install of the CPE unit was pretty easy, but it's pretty loud. Louder than I was expecting it to be. My brother had some aftermarket stuff on his little Focus (Air Intake, Throttle Body, Diablo Chip, etc.) and his intake noise wasn't nearly as loud as the CX7's.
Since it's the wifes car, she's not all that fond of the noise...I heard about it non-stop for a few days but she hasn't said much lately. Or at least not since she filled up and got 22.2 mpg.
It was probably about 40/60 Hwy/City. I'm expecting to get 25mpg or so on the interstate.