The stock barrel is fairly universal, I believe it is a .690 or .693 bore I can't remember off the top of my head, sorry. Paint to bore match is going to give you the best result so match the paint to both barrels and then use whichever one accordingly but you would have even better results if you can afford a barrel kit to match with.
I had an evil pipe kit and stock barrel(obviously).
I never found a difference in the two(I had an evil pipe kit, same thing, but more bore choices). Only difference was that the Evil Pipe kit didn't match the Fusion's looks, and it was louder.