You could do like I did on the Borla. A local indep. exhaust shop charged me $20 to remove and replace the bolts on the cat flange. I then removed the new hardware to install the Borla.
So if I go Y-Pipe, I'll probably have them do that again. It took longer to drive there than it did for them to do the work that morning. And I live about 10 blocks from there!
TB