Well ordered some stuff this weekend includeing 2 high flow cats. Check the boxes to make sure everthing is there and low and behold one is bigger than the other. I look more into it and see that one is 3" and the other is 2 1/2. Should I return it or do you think this will be an issue? I need to get these put on, truck sounds like a boat, and I need to get it emmisions tested.