i agree mate, i've heard from some mechanics that e10 is not a normal fuel formula. it can really reduce a bit of bad gas from the exhaust and it's a bit cheaper but the amount that u can save from using it is not enough to cover the repair fee.
and i think there's lots of things that affect to how long the car runs like tire pressure, alignment, air-con, engine oil and wheel size. some ppl added a turbo, that also increases the fuel usage.