Fabricating the tailpipes is a pretty tricky effort. What we did on mine (Wade Musil - ex Pantera owner did my fabrication) was to take the stock mufflers, and fabricate a jig, and then duplicate the routing of the stock Ansas in 2 1/2" tube.
We spent a lot of time "swinging the suspension" to make sure my pipes had clearance... It helps to take off the wheels, springs/shocks.
The connection we used was one of those "V-Band Clamps". But to use these you would have to modify your collectors. You can see the modified collector in the second picture.
This picture gives you the idea.
If you (or someone else) are doing this - grafting the mufflers on to the tailpipe tubes shouldn't be a big deal. I don't think there would be any advantage to two of the flange clamps, one is easier to deal with.
This last picture shows the 2 1/2" tube going into my stock ANSAs. Of course this was all welded up by the end of the project.
