MAC hpipe
 

I bought a MAC h-pipe a year ago. I just recently had a loud pinging nosie in my h-pipe. I took it off to find that they left a peice of metal on one of the weilds on the O2 sensors. It was a peice of welde wire that was about 3 inches long. That one side broke loose and started to vibrate. What poor quilaty. So yall check your stuff from MAC before you put it on.