Drone comes from cheaply built pipes with thin steel and no insulation. Leaks don't help but it's inherent with all the mass produced exhaust parts that most people can and want to afford. As one who used to build 993 sport cat and delete pipes, we got lucky In having no drone with our parts. We got poo poo'd by the die hards that said what we did shouldn't work but it did with no drone and hp/tq gains. Wish we were still in it sometimes
But you guys won't get zero drone with the common mass market stuff. It's not made well enough.
Just my .00002 cents ( inflation adjusted)