I have the Megan Racing 4 to 1 header 2.5 outlet, Is it going to be a problem bolting it up to the Apexi world sport cat-back???? I remember there being a carbon tapered ring on the header, do I need to buy another one? I just want to be able to put it on my self and not have to take it to a shop. Its a B series header with the civic 97 dx catback, I measured it and the header goes to where the cat-back on the dx starts.