It was just redesigned for 2009 & Mazda typically goes 5 yrs between remodeling. I have not heard of this 1 million mile test. Anything is possible. Maybe they ran an engine on a dyno for 1 million miles before it broke. I'm sure they did preventive maintenance accordingly. But past Mazda 6's have been above average in reliability as well as the smaller Mazda 3. I do like the Mazda 6 indeed, but I would not own one unless it had a V6. But that is out of my current budget.
