Busted Exhaust Gasket

AH-HAH!!!!

The ex-wife's '02 Stang just had the exact same thing happen last week. I too thought it was the gasket or doughnut.
Took it to a local muffler shop and as soon as the guy saw it was a V-6 he said "I'll bet the head pipe is completely broken".
It was, just about two inches below the O2 sensor. Not just cracked, but busted in two pieces. The guy said it's from the water dripping down from the A/C evaporator coil drain. It continuously drips onto the same spot when parked. He also said that just about every V-6 he's seen has done this.
The guy welded it back together. Cost was 20.00.

I have an idea. I'm going to find a 90* barbed nipple. like a vacuum nipple, that fits in the hole then run a rubber tube down and away from the pipe. That should stop the dripping. Once I get it set up I'll post it and let you know what parts to get.