I got my wideband air/fuel kit in today. This may just be a dumb question. lol but better safe then sorry.. The bung has a smaller ridge on one side then the other. just barely not much smaller at all. Does it matter which side is welded? just curious. cause the instructions doesn't really say. I would assume the side that doesnt have the ridge is the side u want to weld against the pipe. Thanks. I will have all 4 of my new gauges installed within the week.. I will be sure to post a pic of inside the car once im finished.