I am trying to make a decision on the exhaust set up and leaning towards 3'' downpipe/ mid pipe and test pipes with oem (stock) catback . Would this set-up completely defeat the purpose due to restriction , what would be the difference in hp gain than having full turbo back . Anyone have anything similar ? . Any opinion , input , first hand This is what im leaning towards http://jhmotorsports.com/shop/catalo...ad46:confused: