My mac H-pipe was excellent, better fitting than the bbk h-pipe I had before. Mac fits better to mac H-pipes, and bbk headers fit better to bbk H-pipes.... And for Headers I like my mac headers alot more than I liked my BBk, my bbk headers didnt fit too well to the bbk-h-pipe, it had some issues fitting., but my mac headers had no issues to bolt up to mac h-pipe.