The Forester came with Ecopia tires, nitrogen filled. Most models of the Impreza come with the 2L engine vs. the 2.5L in the Forester. But, if you have the Crosstrek Limited, it's equipped with the 2.5. Difference could be lots of things, mostly driving style. My wife and I are very efficient drivers who don't start quickly, use the tranny to gain speed and not the accelerator, and we coast when approaching a light. I get 27mpg in town on my Colorado V6 truck, and my neighbor gets 19. I also believe that clean oil and a fresh adaptive package = lower coefficient of drag along with syn. lube in the diff/transmission early on. I check cold tire pressure frequently and use nitrogen. And we live at 3,500' in elev. That's about all the difference I can come with. Our family has had exceptional luck with Subbies. My daughter in-laws Impreza is 11 yrs old.... no issues. My oldest son sold his STI last year after 13 yrs., no issues. He had a previous STI and Baha Turbo. My next oldest son has had several Subbies including the WRX and Forester. My previous Subbie was an Outback Turbo. All seems to deliver good economy.
