mine is an aftermarket true dual exhaust system, they set it up with offset in , center out, back to the bumper. Not sure who installed it, was that way when I bought it. I think a better fit would have been offset in offset out , in my case.
I Went With The American Thunder 2.5 Exhaust System For The 65-66 From Flowmaster And I Was Real Happy With It. Very Neat Clean And Matched . And It Fit Over My Tcp Sub Connectors Also.