just bought a 2004 s4 6 speed with 28k , and had a pre-sale inspection done by a mechanic that specializes in audis , and he made a comment that brought my attention , he said he was not sure if this audi had an aluminum chassis. i googled my question and have read conflicting answers , some say yes others say no.. does anyone have a summary of which years/models have aluminum chassis. in the event of an accident that would be a mayor issue because i've been told that you have to be certified to work on aluminum chassis ..