WHy would it be pointless to go with a 3.6? Its 2lbs of boost and a 3.5 is 3lbs.

Im going to write will an email. I just dont really want to add more stress to my car than i already am. im trying to get this baby to last at least 175k. 3.5 just seems like to much pressure without doing rockers or having actual headers. if a 3.5 is "ok" but borderline, its not worth it.