I just bought a set of first gen muzzys of the forums, and a dual a/f meater. I got the exhaust in today and it don't have the bungs in it like i thought they all did?? It only has one in the back were the two pipes go to 1 and back out to 2. Do i need to install bungs on the headers do getting readings for each cylinder? If i do were would i need to put them????