G&G posted this video detailing the fabrication of one of their GP series exhausts for the Yamaha R6. All of their exhausts are handmade in Italy. I thought it was interesting that most of the non-structural welds on the outside of the can were fusion welds done with the TIG torch and no filler rod. It looks like the base of the exhaust was welded with filler for strength and the baffle on the inside was done with a MIG for convenience since it’s not visible. Like all masters of their craft, this guy makes it look so simple.
Source: YouTube user Pielk