Drain plug is stainless screws with 3M 4200. At the exhaust, at that time a couple others had sheared the heads off stainless screws where the exhaust flange mounted (water pressure against the FAE).... so I used grade 8 screws and 3M 5200. It has never budged. I actually have stainless bolts with the half moon washers so I can thru-bolt it, have just never taken the time to swap them out.