Regarding the 'recommended' octane: My story relates to a 2005 Subaru Outback with the 6 cyl engine. It had a 'recommended' octane of 93, which made it very expensive to operate and it got terrible gas mileage, unless on the freeway, where it got about 31. In town, where I did most of my driving, was dismal. I bought the car new and was using 87 octane with an occasional fill up of 91. I wound up having lots of trouble with the emission system. The O2 sensors failed, the cats failed and were replaced, early on under warranty. The check engine light went on several times and the code shown was the dreaded P0420 code. This code does not say specifically WHAT is wrong with the cat system, just that it is 'not running within specs'. The dealer had to spend considerable time trying to figure out what the cause was. They never asked me what kind of fuel I was using. The car always ran well and passed smog over the years I had it. To make a long and expensive story shorter, the dealer suggested to me that I was using cheap gas and causing the problems. The cat (on 1 side) and sensors that were bad were about $1200. That was the 3rd cat in the car. This car, being a 6 cyl engine, had TWO cats, and FOUR O2 sensors. If anybody can guarantee that using lower octane is ok, put it in writing that the emission control system won't be damaged. I might be leaning away from the turbo model CX5 because of this. I still have to drive both the turbo and non-turbo. The signature model does have some convenience features that I want however and they are not available on the GT (non reserve) model.