I need to replace 2 tyres on my 2009 Outback and wondered what options were available so did a web search. I came across a number of comments that tryes on a legacy must ALL be replaced at the same time as ther must not be a difference in circumference of more than 6 mm ( 1/4 inch ) between any wheel or the diff will be seriously damaged. My Suburu agent has never mentioned this and happily replaced one tyre that had suffered sidewall damage. Is this true? Help please as this could be painful