I installed my exbox today but have a question for anyone else that has this exhuast. Every pipe junction has a spring fastener except for one. where the pipe comes off the rear head into the box itself, there is no spring. Do i need to use a clamp or is the pressure between the two enough to prevent it from leaking? How about using a clamp? The pipe isnt cut in anyway like it usually is when a clamp is used. Help. Thanks!