Re: canadian gas
Petro Canada's the newest refinery out of all of them, and by far the cleanest. I'm a refinery/oilfield inspector, I look at this stuff all the time. That being said, I haven't found a favorite between the 3 (Shell, Esso and Petro Can) thus far, but I haven't tried anything too scary with the truck just yet. Ethanol blended gas is fine as long as you can tune for it. E85 kicks ass, but expect twice the injector, and it's not available around here yet (or maybe never?)
Sunoco isn't available here, I wish to hell it was.