I have a couple of questions....I just got my Injen SES straight tip exhaust and was going to get the TopSpeed Headers and Test Pipes but was wondering 1)I believe the diameter of the Test Pipes is bigger than the Injen exhaust diameter(I think, not for sure) if it is do you see any problem with having a different diameter between these two? 2)Now if I do get the headers and test pipes along with the Injen exhaust do I need to get an ECU flash? My thought is no but I want to make absolutely sure before I get everything and get it installed. Thanks!