@Tdskip I apologize I'm in a giddy mood in advance of the holiday.
Cheapest way to connect the exhuast is with $1.20 worth of bolts.
Best way is to have have
@mb911 fabricate a beautiful system out of Stainless to your specification.
If you go the muffler shop fab route, who knows what you'll get especially if you can't supply the flanges. I've had great shops that do extraordinary work for dirt cheap at times and other times I can tell it was some new Goober they just hired that day that they turned loose with a torch and a MIG.
What ever they do, make sure they provide some sort of support bracket. You don't want the weight of some muffler assembly being suppoted by the headers, they will crack in very short order.
See . . . I tried to be helpful.